Add note about renaming to "inline class" (#2705)

A link to the views feature specification was included in the Flutter@Google newsletter from yesterday. This PR informs anyone who follows that link that the mechanism has been renamed, and points to the PR of inline classes.

Author: eernstg

working/1426-extension-types/feature-specification-views.md

@@ -4,9 +4,18 @@ Author: [email protected]
 
 Status: Draft
 
+**This proposal is now obsolete. The mechanism has been renamed to _inline
+classes_. Please see the [inline class PR][2] for the most recent proposed
+specification.**
+
+[2]: https://github.com/dart-lang/language/pull/2626
+
 
 ## Change Log
 
+2022.12.09
+  - Added notification about renaming to inline classes.
+
 2022.09.22
   - Removed support for `export`, changed `view` to `view class`.