Enable code selection button

Author: johnthagen

mkdocs.yml

@@ -22,6 +22,7 @@ theme:
   features:
     - content.code.annotate
     - content.code.copy
+    - content.code.select
     - content.footnote.tooltips
     - content.tabs.link
     - content.tooltips
@@ -42,9 +43,12 @@ markdown_extensions:
   - footnotes
   - pymdownx.details
   - pymdownx.keys
-  - pymdownx.highlight
-  - pymdownx.superfences
+  - pymdownx.highlight:
+      anchor_linenums: true
+      line_spans: __span
+      pygments_lang_class: true
   - pymdownx.snippets
+  - pymdownx.superfences
   - pymdownx.tabbed:
       alternate_style: true
       slugify: !!python/object/apply:pymdownx.slugs.slugify