Fixed links to Python Markdown documentation

docs/extensions/admonition.md

@@ -4,7 +4,7 @@
 makes it possible to add block-styled side content to your documentation, for
 example summaries, notes, hints or warnings.
 
-  [1]: https://pythonhosted.org/Markdown/extensions/admonition.html
+  [1]: https://python-markdown.github.io/extensions/admonition/
 
 ## Installation
 

docs/extensions/codehilite.md

@@ -10,7 +10,7 @@ executed during compilation of the Markdown file.
     further directions on how to set up Pygments or use the official
     [Docker image][3] with all dependencies pre-installed.
 
-  [1]: https://pythonhosted.org/Markdown/extensions/code_hilite.html
+  [1]: https://python-markdown.github.io/extensions/code_hilite/
   [2]: http://pygments.org
   [3]: https://hub.docker.com/r/squidfunk/mkdocs-material/
 

docs/extensions/footnotes.md

@@ -3,7 +3,7 @@
 [Footnotes][1] is another extension included in the standard Markdown library.
 As the name says, it adds the ability to add footnotes to your documentation.
 
-  [1]: https://pythonhosted.org/Markdown/extensions/footnotes.html
+  [1]: https://python-markdown.github.io/extensions/footnotes/
 
 ## Installation
 

docs/extensions/metadata.md

@@ -7,7 +7,7 @@ source: metadata.md
 The [Metadata][1] extension makes it possible to add metadata to a document
 which gives more control over the theme in a page-specific context.
 
-  [1]: https://pythonhosted.org/Markdown/extensions/meta_data.html
+  [1]: https://python-markdown.github.io/extensions/meta_data/
 
 ## Installation
 

docs/extensions/permalinks.md

@@ -5,7 +5,7 @@ of the standard Markdown library. The extension inserts an anchor at the end of
 each headline, which makes it possible to directly link to a subpart of the
 document.
 
-  [1]: https://pythonhosted.org/Markdown/extensions/toc.html
+  [1]: https://python-markdown.github.io/extensions/toc/
 
 ## Installation
 

docs/extensions/pymdown.md

@@ -238,7 +238,7 @@ lists and other block elements, which the [Fenced Code Blocks][23] extension
 from the standard Markdown library doesn't parse correctly.
 
   [22]: https://facelessuser.github.io/pymdown-extensions/extensions/superfences/
-  [23]: https://pythonhosted.org/Markdown/extensions/fenced_code_blocks.html
+  [23]: https://python-markdown.github.io/extensions/fenced_code_blocks/
 
 ### Tasklist