[RFC FS-1110, 1111] index syntax and ref cell op deprecation (dotnet#11900)

* indexer notation expr[expr]

* add tests

* back compat

* update tests

* fix build

* fix build

* fix additional case of syntactic sugar triggering warning

* fix warning#

* fix warnings

* fix warning#

* improve messages

* remvoe test case no longer of interest

* emit informationals

* update baselines

* don't produce informationals for expr.[idx] as yet

* tweak error messages

* remove dead code

* merge main

* fix tests

* fix tests

* fix tests

* fix tests

* improve diagnostics

* add aka.ms links

* update baselines

* fix error messages

* change warning to informational in preview

* fix test

* code review feedback

* code review feedback

* Update salsa.fs

Co-authored-by: Don Syme <[email protected]>

Author: dsyme

Structure/BlockStructureService.fs

@@ -23,7 +23,7 @@ module internal BlockStructure =
         | Scope.Interface
         | Scope.TypeExtension
         | Scope.RecordDefn
-        | Scope.CompExpr
+        | Scope.ComputationExpr
         | Scope.ObjExpr
         | Scope.UnionDefn
         | Scope.Attribute
@@ -49,7 +49,6 @@ module internal BlockStructure =
         | Scope.IfThenElse-> FSharpBlockTypes.Conditional
         | Scope.Tuple
         | Scope.ArrayOrList
-        | Scope.CompExprInternal
         | Scope.Quote
         | Scope.SpecialFunc
         | Scope.Lambda
@@ -84,7 +83,7 @@ module internal BlockStructure =
         | Scope.Interface
         | Scope.TypeExtension
         | Scope.RecordDefn
-        | Scope.CompExpr
+        | Scope.ComputationExpr
         | Scope.ObjExpr
         | Scope.UnionDefn
         | Scope.Type
@@ -104,7 +103,6 @@ module internal BlockStructure =
         | Scope.IfThenElse
         | Scope.Tuple
         | Scope.ArrayOrList
-        | Scope.CompExprInternal
         | Scope.Quote
         | Scope.Lambda
         | Scope.LetOrUseBang