[3.12] gh-83505: Add markdown mimetype mapping (GH-17995) (#118594)

gh-83505: Add markdown mimetype mapping (GH-17995)
(cherry picked from commit b6f0ab5)

Co-authored-by: Ryan Batchelder <[email protected]>

Author: miss-islington

Lib/mimetypes.py

@@ -551,6 +551,8 @@ def _default_mime_types():
         '.csv'    : 'text/csv',
         '.html'   : 'text/html',
         '.htm'    : 'text/html',
+        '.md'     : 'text/markdown',
+        '.markdown': 'text/markdown',
         '.n3'     : 'text/n3',
         '.txt'    : 'text/plain',
         '.bat'    : 'text/plain',

Misc/NEWS.d/next/Library/2020-01-14-09-46-51.bpo-39324.qUcDrM.rst

@@ -0,0 +1 @@
+Add mime type mapping for .md <-> text/markdown