Bind compound assignment operator declarations

[AlekseyTs]

No description provided.

[cston]

            ">>=" => WellKnownMemberNames.RightShiftAssignmentOperatorName,

Consider using CompoundAssignmentOperatorNameFromSyntaxKind() in all cases, to test all code paths in that method.

var kind = op switch
{
    ">>=" => SyntaxKind.GreaterThanGreaterThanEqualsToken,
    ">>>=" => SyntaxKind.GreaterThanGreaterThanGreaterThanEqualsToken,
    _ => SyntaxFactory.ParseToken(op).Kind(),
};
return OperatorFacts.CompoundAssignmentOperatorNameFromSyntaxKind(kind, isChecked: isChecked);
``` #Resolved

---
Refers to: src/Compilers/CSharp/Test/Emit3/Symbols/UserDefinedCompoundAssignmentOperatorsTests.cs:5979 in cba3fb7. [](commit_id = cba3fb72c94c88a493c6533271e6e8a33c6b3fa8, deletion_comment = False)

[cston]

(structure ? "struct" : "class") + @" C1

Also test interface? #Resolved

---

Refers to: src/Compilers/CSharp/Test/Emit3/Symbols/UserDefinedCompoundAssignmentOperatorsTests.cs:6001 in cba3fb7. [](commit_id = cba3fb7, deletion_comment = False)

[AlekseyTs]

@333fred, @dotnet/roslyn-compiler For the second review

[AlekseyTs]

@333fred, @dotnet/roslyn-compiler For the second review