Clarify xUnit migration docs #4798

Problem Statement

Step 3 of the xUnit migration docs states "You should see TUXU0001 warnings in your build output for xUnit code that can be converted.". But TUXU0001 is information level and won't be in the output of dotnet build, so this step leads to confusion that the analyzer isn't working, even though it is working.

Proposed Solution

Remove this step and skip straight to applying changes, or explain that the analyzer outputs can be viewed without being applied with dotnet format analyzers --severity info --diagnostics TUXU0001 --verify-no-changes

Alternatives Considered

No response

Feature Category

Documentation

How important is this feature to you?

Nice to have - would improve my experience

Additional Context

No response

Contribution

• I'm willing to submit a pull request for this feature