build(mkdocs): improve configuration and fix paths

- Fix trailing slashes in custom_dir and modules paths for consistency
- Enable caching for include-markdown plugin to improve build performance
- Adjust watch list formatting and remove unnecessary entries
- Update comment style for better template rendering

These changes ensure proper path resolution and improve build performance while maintaining consistent configuration formatting.

Author: liblaf

template/.config/copier/mkdocs.yaml.jinja

@@ -1,4 +1,4 @@
-# -*- mode: yaml; -*-
+# {#- -*- mode: yaml; -*- -#}
 # This file is @generated by <https://github.com/liblaf/copier-python>.
 # DO NOT EDIT!
 
@@ -27,7 +27,7 @@ extra_javascript:
 
 theme:
   name: material
-  custom_dir: docs/overrides/
+  custom_dir: docs/overrides
   features:
     # - announce.dismiss
     - content.action.edit
@@ -106,6 +106,7 @@ plugins:
 
   # ----------- External plugins, schema provided by our community ----------- #
   include-markdown:
+    cache: 600
   git-revision-date-localized:
     enable_creation_date: true
   mkdocstrings:
@@ -212,7 +213,7 @@ plugins:
 
   api-autonav: # ref: <https://github.com/tlambert03/mkdocs-api-autonav>
     modules:
-      - "src/{{ wheel_package_dir }}/"
+      - "src/{{ wheel_package_dir }}"
 
   # hippogriffe: # ref: <https://github.com/patrick-kidger/hippogriffe>
   # hippogriffe requires `mkdocstrings.python.options.force_inspection: true`. (This is so it can do things like display type annotations correctly.)
@@ -256,7 +257,6 @@ markdown_extensions:
   mdx_truly_sane_lists:
 
 watch:
-  - .config/copier/mkdocs.yaml
-  - docs/
+  - docs
   - README.md
-  - src/
+  - src