feat: Add copy_standard_markdown parameter to plugin

This parameter controls whether the standard markdown extensions will
  be added to the include_extensions or not.

  Resolves #1.

mkdocs.yml

@@ -6,13 +6,18 @@ plugins:
 - search
 - semiliterate:
     merge_docs_dir: false
-    ignore_folders: [dist]
+    ignore_folders: [dist, build]
     include_extensions: [LICENSE]
-#    semiliterate:
-#      - pattern: '(\.md)$'
-#        replace: [['^(.*)<!-- repo: -->.*<!-- site:(.*?) -->(.*\s*)$', '\1\2\3']]
+    semiliterate:
+      - pattern: '(\.md)$'
+        start: '^(.*\s*)'
+        replace: [['^(.*)<!-- repo: -->.*<!-- site:(.*?) -->(.*\s*)$', '\1\2\3']]
+      - pattern: '(\.py)$'
+        start: '"""\smd'
+        stop: '"""'
 markdown_extensions:
 - abbr
+- def_list
 theme:
   name: readthedocs
 docs_dir: mkdocs_semiliterate # dummy