Add a mkdocs extension to generate the --help output (#720)

* Add a mkdocs extension to generate the --help output

* Add the correct setuptools syntax for relative requirements

* docs: use macro plugin instead

* docs: remove indirection in docs

Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

mkdocs.yml

@@ -41,3 +41,7 @@ markdown_extensions:
 plugins:
   - include-markdown
   - search
+  - macros:
+      module_name: docs/main
+      j2_variable_start_string: «
+      j2_variable_end_string: »