Completing a generic parameter to a nested type `Outer.Nested<#^COMPLETE^#>` crashed when used to initialize a local variable and returned no results when initializing a global variable.
This is because the generic argument parsing logic for nested types inside `parseExprPostfixSuffix` didn’t match that of global types in `parseExprIdentifier`. Make sure they do the same thing semantically.
Fixes rdar://77909679 [SR-14627]
Due to https://github.com/apple/swift/pull/36552, parsing the code completion token as a type inside a generic parameter list no longer fails. Instead, it consumes the code completion token as a type identifier. However, since `parseExprIdentifer` does not return a `ParserStatus`, the information whether a code completion token was consumed gets lost, causing `setCodeCompletionDelayedDeclState` to not be called and thus no code completion results show up.
To resolve this, make `parseExprIdentifier` return its `ParserStatus` through a `ParserResult`.
Fixes rdar://76335452 [SR-14432]
