fix(csharp): stop tuple-typed properties losing their name to the method branch

[AmirF194]

Checklist

• This PR follows the guidelines in CONTRIBUTING.md regarding the scope of PRs.
• For changes that add features or fix problems, I have added an entry to CHANGELOG.md, which concisely describes the change.

_extract_base_name_and_type splits Roslyn's "Name : Type" property names by checking for ( anywhere in the raw string. A C# tuple type is written with parens, e.g. (int X, string Y), so a tuple-typed property tripped that check and fell into the method branch instead, keeping the trailing " :" in the reported name ("Position :" instead of "Position"). Since find_symbol defaults to exact name matching, such a property becomes unfindable by its real name.

Narrowed the ( check to the segment before the first " : ", so a parenthesis inside the type no longer affects branch selection. Checked it doesn't regress a method that returns a tuple or takes tuple-typed parameters, both of which still have ( before that segment.

Added TestCSharpExtractBaseNameAndType. The new test fails without the change ("Position :") and passes with it. poe lint and codespell are clean. I didn't capture a live Roslyn trace for the tuple case specifically, the expected "Name : Type" format is the same pattern the existing tests already confirm live for non-tuple properties, plus standard C# tuple syntax, so this rests on that plus the language spec rather than an observed wire capture.

[opcode81]

Since the modified method _extract_base_name_and_type is called by _normalize_symbol_name, the change must invalidate the high-level symbol cache by incrementing this version. See docstring of _normalize_symbol_name in base class.

[AmirF194]

Good catch, missed that this changes what the cache stores. Bumped normalize_symbol_name_version to 2 in _document_symbols_cache_fingerprint, pushed as 8f2406d.