Documentation (#8058)

* docs(publish your site): Add caching for gitlab pipeline

* docs(publish your site): Add comments

Author: niclasheinz

docs/publishing-your-site.md

@@ -181,13 +181,21 @@ contents:
       script:
         - pip install mkdocs-material
         - mkdocs build --site-dir public
+      cache:
+        key: ${CI_COMMIT_REF_SLUG}
+        paths:
+          - .cache/ # (1)!
       artifacts:
         paths:
           - public
       rules:
         - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
+
     ```
 
+    1.  Some Material for MkDocs plugins use [caching] to speed up repeated
+        builds, and store the results in the `.cache` directory.
+
 === "Insiders"
 
     ``` yaml
@@ -197,6 +205,10 @@ contents:
       script: # (1)!
         - pip install git+https://${GH_TOKEN}@github.com/squidfunk/mkdocs-material-insiders.git
         - mkdocs build --site-dir public
+      cache:
+        key: ${CI_COMMIT_REF_SLUG}
+        paths:
+          - .cache/ # (2)!
       artifacts:
         paths:
           - public
@@ -208,6 +220,9 @@ contents:
         [personal access token] when deploying [Insiders], which can be done
         using [masked custom variables].
 
+    2.  Some Material for MkDocs plugins use [caching] to speed up repeated
+        builds, and store the results in the `.cache` directory.
+
 Now, when a new commit is pushed to the [default branch] (typically `master` or
 `main`), the static site is automatically built and deployed. Commit and push
 the file to your repository to see the workflow in action.