Add some sexy new mkdocs plugins

requirements.txt

@@ -3,3 +3,5 @@ mkdocs-material>=4.4.3
 pymdown-extensions>=6.0
 Markdown>=3.0.1
 mkdocs-minify-plugin>=0.2
+mkdocs-autolinks-plugin>=0.2.0
+mkdocs-htmlproofer-plugin>=0.0.3