Remove markdown-include and use snippets instead

Signed-off-by: yubiuser <github@yubiuser.dev>

docs/api/auth.md

@@ -418,4 +418,3 @@ Session-based authentication, while convenient and widely used, does have severa
 
 Remember, no security measure is foolproof, but by understanding the potential risks and the multiple layers of defense your Pi-hole implemented against these risks, you can make an informed decision about how to use the Pi-hole API securely in the context of your own scripts. Always use the secure transmission method (HTTPS) offered by your Pi-hole to access the API. The strong encryption will prevent attackers from eavesdropping on your requests and makes stealing your session ID basically impossible.
 
-{!abbreviations.md!}

docs/api/index.md

@@ -200,4 +200,3 @@ Code | Description | Interpretation
 
 We recommend writing code that gracefully handles all possible API exceptions. The Pi-hole API is designed to support this by standardized error messages and human-readable hints for errors.
 
-{!abbreviations.md!}

mkdocs.yml

@@ -85,15 +85,11 @@ markdown_extensions:
   # Adds the ability to define abbreviations (https://squidfunk.github.io/mkdocs-material/reference/tooltips/)
   - abbr
   - attr_list
-  # Include files in other documents like {!some/dir/in/docs/filename.md!}
-  - markdown_include.include:
-      base_path: docs
   - pymdownx.snippets:
       # auto_append abbreviations.md to every file
       # https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary
       auto_append:
         - docs/abbreviations.md
-  # Include files in other documents like {!some/dir/in/docs/filename.md!}
   # Metadata support in pages
   # (https://squidfunk.github.io/mkdocs-material/extensions/metadata/)
   - meta