Add cs/string-concatenation-in-loop to the quality suite

[tamasvajk]

This PR is adding the cs/string-concatenation-in-loop query to the code-quality suite. I've ran the query on MRVA and then manually checked autofix suggestions. The results and the fixes are sensible.

• MRVA looks good
• need to check autofix (might need more compliant/non-compliant samples)

[Copilot]

Pull Request Overview

This PR integrates the new cs/string-concatenation-in-loop performance rule into the C# code-quality suite.

• Adds the quality tag to the rule’s metadata.
• Includes the new query in the csharp-code-quality.qls.expected suite file.

Reviewed Changes

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

File	Description
csharp/ql/src/Performance/StringConcatenationInLoop.ql	Added quality to the @tags list in the rule header
csharp/ql/integration-tests/posix/query-suite/csharp-code-quality.qls.expected	Registered the new query in the expected suite output

Comments suppressed due to low confidence (1)

csharp/ql/integration-tests/posix/query-suite/csharp-code-quality.qls.expected:14

• Integration tests now include the new query in the suite, but there are no corresponding positive and negative test fixtures (e.g., sample C# files) to verify that the rule correctly flags string-concatenation-in-loop cases and accepts compliant code. Consider adding .qltest scenarios under integration-tests to cover both compliant and non-compliant patterns.

ql/csharp/ql/src/Performance/StringConcatenationInLoop.ql

[michaelnebel]

Looks good!
Is there a corresponding PR in the codeql-autofix repo that adds it to the CCR suite (maybe that is not needed either?).

[tamasvajk]

Looks good! Is there a corresponding PR in the codeql-autofix repo that adds it to the CCR suite (maybe that is not needed either?).

I didn't update that suite. Should I?

[tamasvajk]

@michaelnebel What do you think, do we need a change note? (I think we don't)

[michaelnebel]

@michaelnebel What do you think, do we need a change note? (I think we don't)

We shouldn't add a change note when adding a query to the code-quality suite.

[michaelnebel]

Looks good! Is there a corresponding PR in the codeql-autofix repo that adds it to the CCR suite (maybe that is not needed either?).

I didn't update that suite. Should I?

Not sure, whether this suite was only consumed by the suite that was used by the now disabled feature flag - I have been updating it, but maybe it is not needed. Will ask in Slack.