Update Language Feature Status.md and Update Compiler Test Plan.md for instance operators (#78460)

Author: AlekseyTs

docs/Language Feature Status.md

@@ -10,7 +10,6 @@ efforts behind them.
 
 | Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
 | ------- | ------ | ----- | --------- | -------- | --------- | --------- |
-| [User Defined Compound Assignment Operators](https://github.com/dotnet/csharplang/issues/9101) | [UserDefinedCompoundAssignment](https://github.com/dotnet/roslyn/tree/features/UserDefinedCompoundAssignment) | [In Progress](https://github.com/dotnet/roslyn/issues/76934) | [AlekseyTs](https://github.com/AlekseyTs) | [333fred](https://github.com/333fred), [cston](https://github.com/cston) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [AlekseyTs](https://github.com/AlekseyTs) |
 | Runtime Async | [runtime-async](https://github.com/dotnet/roslyn/tree/features/runtime-async) | [In Progress](https://github.com/dotnet/roslyn/issues/75960) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [RikkiGibson](https://github.com/RikkiGibson) |  |  |
 | [`field` keyword in properties](https://github.com/dotnet/csharplang/issues/140) | [field-keyword](https://github.com/dotnet/roslyn/tree/features/field-keyword) | [Merged into 17.12p3](https://github.com/dotnet/roslyn/issues/57012) | [Youssef1313](https://github.com/Youssef1313), [cston](https://github.com/cston) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
 | [First-class Span Types](https://github.com/dotnet/csharplang/issues/7905) | [FirstClassSpan](https://github.com/dotnet/roslyn/tree/features/FirstClassSpan) | [Merged into 17.13p1](https://github.com/dotnet/roslyn/issues/73445) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [333fred](https://github.com/333fred) | | [333fred](https://github.com/333fred), [stephentoub](https://github.com/stephentoub) |
@@ -22,6 +21,7 @@ efforts behind them.
 | [Null-conditional assignment](https://github.com/dotnet/csharplang/issues/6045) | [null-conditional-assignment](https://github.com/dotnet/roslyn/tree/features/null-conditional-assignment) | [Merged into 17.14p3](https://github.com/dotnet/roslyn/issues/75554) | [RikkiGibson](https://github.com/RikkiGibson) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [RikkiGibson](https://github.com/RikkiGibson) |
 | [Ignored directives](https://github.com/dotnet/csharplang/issues/8617) | [PR](https://github.com/dotnet/roslyn/pull/77696) | Merged into 17.14p3 | [jjonescz](https://github.com/jjonescz) | [RikkiGibson](https://github.com/RikkiGibson), [jaredpar](https://github.com/jaredpar) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [jaredpar](https://github.com/jaredpar) |
 | [Dictionary expressions](https://github.com/dotnet/csharplang/issues/8659) | [dictionary-expressions](https://github.com/dotnet/roslyn/tree/features/dictionary-expressions) | [Preview merged into 17.14p3](https://github.com/dotnet/roslyn/issues/76310) | [cston](https://github.com/cston), [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [333fred](https://github.com/333fred), [jcouv](https://github.com/jcouv) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
+| [User Defined Compound Assignment Operators](https://github.com/dotnet/csharplang/issues/9101) | [UserDefinedCompoundAssignment](https://github.com/dotnet/roslyn/tree/features/UserDefinedCompoundAssignment) | [Merged to main](https://github.com/dotnet/roslyn/issues/76934) | [AlekseyTs](https://github.com/AlekseyTs) | [333fred](https://github.com/333fred), [cston](https://github.com/cston) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [AlekseyTs](https://github.com/AlekseyTs) |
 
 # Working Set VB
 

docs/contributing/Compiler Test Plan.md

@@ -248,8 +248,8 @@ A variable is a storage location. These are all the different ways to refer to a
 x.y 
 f( ) 
 a[e] 
-x++ 
-x-- 
+x++ (including instance user defined)
+x-- (including instance user defined)
 new X() 
 new() 
 typeof(T) 
@@ -263,8 +263,8 @@ delegate ( ) { }
 !x 
 ~x 
 ^x
-++x 
---x 
+++x (including instance user defined)
+--x (including instance user defined)
 (X)x 
 x * y 
 x / y 
@@ -290,17 +290,17 @@ x || y
 x ?? y 
 x ? : y : z
 x = y 
-x *= y 
-x /= y 
-x %= y 
-x += y 
-x -= y 
-x <<= y 
-x >>= y 
-x >>>= y 
-x &= y 
-x ^= y 
-x |= y 
+x *= y (including instance user defined)
+x /= y (including instance user defined)
+x %= y (including instance user defined)
+x += y (including instance user defined)
+x -= y (including instance user defined)
+x <<= y (including instance user defined)
+x >>= y (including instance user defined)
+x >>>= y (including instance user defined)
+x &= y (including instance user defined)
+x ^= y (including instance user defined)
+x |= y (including instance user defined)
 x ??= y
 x => { } 
 sizeof( ) 
@@ -387,7 +387,7 @@ __makeref( x )
 - Interface method 
 - Field
 - User-defined indexer
-- User-defined operator (including checked)
+- User-defined operator (including checked, including instance increment/decrement and compound assignment)
 - User-defined conversion (including checked)
 
 ## Patterns