Bump the trunk major version to 11

and clear the release notes.

Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 5852475e2c049ce29dcb1f0da3ac33035f8c9156
diff --git a/docs/conf.py b/docs/conf.py
index 44935b6..70fb71f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -48,9 +48,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '10.0'
+version = '11.0'
 # The full version, including alpha/beta/rc tags.
-release = '10.0'
+release = '11.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.