Bump the trunk major version to 14

and clear the release notes.

NOKEYCHECK=True
GitOrigin-RevId: 08c766a7318ab37bf1d77e0c683cd3b00e700877
diff --git a/docs/conf.py b/docs/conf.py
index 07ffba7..bc91d90 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -48,9 +48,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '13.0'
+version = '14.0'
 # The full version, including alpha/beta/rc tags.
-release = '13.0'
+release = '14.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.