Improve parser error recovery for underscore-dot patterns

[evgTSV]

Description

Refactored pars.fsy to split UNDERSCORE DOT pathOp into granular rules, adding explicit error recovery for missing identifiers after a dot. Introduced underscoreLongIdentPat to centralize underscore-prefixed long identifier logic, updating related rules and replacing access UNDERSCORE DOT pathOp with access underscoreLongIdentPat. Updated Member 11.fs.bsl baseline: wildcard member patterns now parse as Named instead of FromParseError (Wild, ...), and error messages are more precise ("Identifier expected", "Expecting member body").

[evgTSV]

The following failed test has appeared:
failed FSharp.Editor.Tests.CompletionProviderTests.Completion list for override does not contain virtual method if it is already overridden in the same type

ReSharper-FSharp handles this correctly, the failure in FSharp.Editor suggests a dependency on previous broken AST states in its completion logic

[github-actions]

❗ Release notes required

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@evgTSV,

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Change path	Release notes path	Description
`src/Compiler`	docs/release-notes/.FSharp.Compiler.Service/11.0.100.md	No release notes found or release notes format is not correct

[github-actions]

🔍 Tooling Safety Check — Affects-Bootstrap, Affects-Compiler-Output
Affects-Bootstrap: modifies pars.fsy (parser generator input used during bootstrap)
Affects-Compiler-Output: changes parser error recovery affecting AST shape

Generated by PR Tooling Safety Check · opus46 2.8M · ◷

[evgTSV]

Please note that the test erroneously passed as successful.

Let's see what is happening:

type G<'a> () =
    override _.

    override x.ToString () = ""
    
...

type B () =
    inherit A ()

    override A1 () = ()
    override x.b

It doesn't take long to notice that override x.b has an identifier after selfId, while override _. doesn't. The first override (in type G) should have provided all overrides (including override x.ToString () = ""), but why didn't it, and why was the test successful? I guess that including changes in the parser started to correctly handle underscore as an identifier, so the internal logic no longer skips override _.. My approach is to do the same as in type B - to add an identifier after the dot.