Issue #22118: Switch urllib.parse to use RFC 3986 semantics for the resolution of relative URLs, rather than RFCs 1808 and 2396.

Patch by Demian Brecht.
diff --git a/Doc/library/urllib.parse.rst b/Doc/library/urllib.parse.rst
index b951420..3675305 100644
--- a/Doc/library/urllib.parse.rst
+++ b/Doc/library/urllib.parse.rst
@@ -267,6 +267,11 @@
    :func:`urlunsplit`, removing possible *scheme* and *netloc* parts.
 
 
+   .. versionchanged:: 3.5
+
+      Behaviour updated to match the semantics defined in :rfc:`3986`.
+
+
 .. function:: urldefrag(url)
 
    If *url* contains a fragment identifier, return a modified version of *url*