Merge pull request #2620 from talkerbox/improve-access-log-format-docs

Improve access-log-format documentation section

docs/source/settings.rst

@@ -200,7 +200,7 @@ Identifier   Description
 ===========  ===========
 h            remote address
 l            ``'-'``
-u            user name
+u            user name (if HTTP Basic auth used)
 t            date of the request
 r            status line (e.g. ``GET / HTTP/1.1``)
 m            request method