Help: Drop 3.22 release note for VS 2022

The 3.21.4 release will have full support, so it is not new to
the 3.22 series anymore.

Help/release/3.22.rst

@@ -142,7 +142,3 @@ Other Changes
   This became available as of VS 16.10 (toolchain version 14.29.30037).
 
 * The :cpack_gen:`CPack NSIS Generator` now requires NSIS 3.03 or later.
-
-* The :generator:`Visual Studio 17 2022` generator was updated.  This is
-  experimental and based on "Visual Studio 2022 Release Candidate" because
-  this version of VS has not been released.