Static extension members for `enum` type are not part of IntelliSense

[just-ero]

Full issue information + repro project:
https://github.com/just-ero/roslyn-issues-repros/tree/main/5.0.0/006_EnumExtensionResolution

Version

Note

Roslyn: 5.0.0-1.25361.2 (fdd628a)
.NET SDK: 10.0.100-preview.6.25358.103

Visual Studio Code: 1.102.1
C# Extension: 2.86.19
C# Dev Kit Extension: 1.40.25

Steps to Reproduce

1. Add the following code wherever syntactically applicable:

   enum E;
   
   static class EExt
   {
       extension(E)
       {
           public static void M() { }
       }
   }

2. Type E. to see suggested members. This can be in the same file.

Expected Behavior

M is listed as a static method on E.

Actual Behavior

It is not.

[CyrusNajmabadi]

Fix is trivial. Working on it