fix(docs): follow GitLab's move of the Mattermost notifications page

docs.gitlab.com/user/project/integrations/mattermost_notifications/ now
answers 404, which fails test_urls_reachable in test-external on every
pull request (job 126163816094 on #1358). GitLab serves the same page,
titled "Mattermost notifications", under .../integrations/mattermost/.
Both EDGES copies point there, and `make integration-matrix` regenerated
the one cell of 027-integration-matrix.md that carries the link.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cli/build/docs/integration_matrix/__main__.py

@@ -241,7 +241,7 @@ EDGES = [
     (
         "gitlab",
         "mattermost",
-        "https://docs.gitlab.com/user/project/integrations/mattermost_notifications/",
+        "https://docs.gitlab.com/user/project/integrations/mattermost/",
         "check",
     ),
     ("gitlab", "jira", "https://docs.gitlab.com/integration/jira/", "check"),

cli/build/docs/integration_matrix/data.py

@@ -230,7 +230,7 @@ EDGES: list[tuple[str, str, str, str]] = [
     (
         "gitlab",
         "mattermost",
-        "https://docs.gitlab.com/user/project/integrations/mattermost_notifications/",
+        "https://docs.gitlab.com/user/project/integrations/mattermost/",
         "check",
     ),
     ("gitlab", "jira", "https://docs.gitlab.com/integration/jira/", "check"),

docs/requirements/027-integration-matrix.md

@@ -49,7 +49,7 @@ Notes:
 | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | — | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | ❌ | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **fusiondirectory** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **fusiondirectory** | [☑️](../../roles/web-app-fusiondirectory/meta/services.yml) | ❌ | ❌ | ❌ |
 | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | — | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | ❌ | ❌ | **gitea** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitea** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **gitea** | [☑️](../../roles/web-app-gitea/meta/services.yml) | ❌ | ❌ | ❌ |
 | ↓ row wires → col | akaunting | baserow | bigbluebutton | bluesky | bookwyrm | bridgy-fed | chess | confluence | dashboard | decidim | ↓ row wires → col | discourse | erpnext | espocrm | fediwall | fider | flowise | friendica | funkwhale | fusiondirectory | gitea | ↓ row wires → col | gitlab | hugo | jenkins | jira | jitsi | joomla | keycloak | kix | lam | listmonk | ↓ row wires → col | litellm | littlejs | magento | mailu | mastodon | matomo | matrix | mattermost | mediawiki | mig | ↓ row wires → col | minio | mini-qr | mobilizon | moodle | n8n | navigator | nextcloud | odoo | opencloud | openproject | ↓ row wires → col | opentalk | openwebui | peertube | pgadmin | phpldapadmin | phpmyadmin | pixelfed | postmarks | pretix | prometheus | ↓ row wires → col | roulette-wheel | shopware | snipe-it | socialhome | sphinx | suitecrm | taiga | wordpress | xwiki | yourls | ↓ row wires → col | zammad | asset | cdn | collabora | coturn | css | file | html | legal | libretranslate | ↓ row wires → col | logout | onlyoffice | simpleicons | xmpp |
-| **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [✅](https://docs.gitlab.com/user/project/integrations/confluence/) | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | — | ❌ | [✅](https://docs.gitlab.com/integration/jenkins/) | [✅](https://docs.gitlab.com/integration/jira/) | ❌ | ❌ | [✅](https://docs.gitlab.com/integration/saml/) | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | [✅](https://docs.gitlab.com/user/project/integrations/matrix/) | [✅](https://docs.gitlab.com/user/project/integrations/mattermost_notifications/) | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **gitlab** | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | ❌ | ❌ |
+| **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [✅](https://docs.gitlab.com/user/project/integrations/confluence/) | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | — | ❌ | [✅](https://docs.gitlab.com/integration/jenkins/) | [✅](https://docs.gitlab.com/integration/jira/) | ❌ | ❌ | [✅](https://docs.gitlab.com/integration/saml/) | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | [✅](https://docs.gitlab.com/user/project/integrations/matrix/) | [✅](https://docs.gitlab.com/user/project/integrations/mattermost/) | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **gitlab** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **gitlab** | [☑️](../../roles/web-app-gitlab/meta/services.yml) | ❌ | ❌ | ❌ |
 | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **hugo** | ❌ | — | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | ❌ | ❌ | **hugo** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **hugo** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **hugo** | [☑️](../../roles/web-app-hugo/meta/services.yml) | ❌ | ❌ | ❌ |
 | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jenkins/meta/services.yml) | ❌ | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [✅](https://plugins.jenkins.io/gitea/) | **jenkins** | [✅](https://plugins.jenkins.io/gitlab-plugin) | ❌ | — | ❌ | ❌ | ❌ | [✅](https://plugins.jenkins.io/oic-auth/) | ❌ | ❌ | ❌ | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jenkins/meta/services.yml) | ❌ | [✅](https://plugins.jenkins.io/mattermost/) | ❌ | ❌ | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [✅](https://plugins.jenkins.io/prometheus) | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **jenkins** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jenkins/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **jenkins** | [☑️](../../roles/web-app-jenkins/meta/services.yml) | ❌ | ❌ | ❌ |
 | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **jira** | ❌ | ❌ | ❌ | — | ❌ | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | ❌ | ❌ | **jira** | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | **jira** | ❌ | ❌ | ❌ | ❌ | ❌ | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | ❌ | ❌ | ❌ | **jira** | [☑️](../../roles/web-app-jira/meta/services.yml) | ❌ | ❌ | ❌ |