C#: Increase precision of cs/useless-gethashcode-call.

[michaelnebel]

As this table indicates, only byte, sbyte, short, ushort and int can use the identity function for GetHashCode (and they indeed do so) as the return type of GetHashCode is int.
In this PR we update the cs/useless-gethashcode-call to exclude calls to GetHashCode on uint, long and ulong and convert the tests to inline tests.

[Copilot]

Pull Request Overview

This PR increases the precision of the cs/useless-gethashcode-call query by excluding calls to GetHashCode on uint, long, and ulong from being flagged. It also converts the tests to inline tests and updates the change note accordingly.

• Updated change note file to document the refined behavior.
• Modified the test file to flag only calls on int, short, ushort, byte, and sbyte.

Reviewed Changes

Copilot reviewed 2 out of 5 changed files in this pull request and generated no comments.

File	Description
csharp/ql/src/change-notes/2025-03-13-useless-gethashcode-call.md	Adds a change note specifying the increased precision.
csharp/ql/test/query-tests/Useless Code/IntGetHashCode/IntGetHashCode.cs	Converts tests to inline tests with alerts for specific types.

Files not reviewed (3)

• csharp/ql/src/Useless code/IntGetHashCode.ql: Language not supported
• csharp/ql/test/query-tests/Useless Code/IntGetHashCode/IntGetHashCode.expected: Language not supported
• csharp/ql/test/query-tests/Useless Code/IntGetHashCode/IntGetHashCode.qlref: Language not supported

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[michaelnebel]

DCA looks good.