Handle labeled previous statements in cuddle checks to avoid false positives on if

[Copilot]

wsl could incorrectly report missing whitespace above this line (invalid statement above if) when an if followed a labeled statement, even when the labeled statement wrapped a valid assignment. The check was evaluating *ast.LabeledStmt directly instead of the underlying statement kind.

• Parser logic: unwrap labeled statements before validation

  • Added unlabeledStmt(ast.Node) ast.Node to peel nested *ast.LabeledStmt wrappers.
  • Updated cuddle/type validation path to use the unwrapped previous statement when checking allowed previous statement types and identifier intersection.

• Behavioral coverage: labeled assignment above if

  • Added focused testdata in default_config/if for a loop label followed by err := ... and if err != nil, asserting no false-positive whitespace diagnostic.

for {
LABEL:
    _, err := fn()
    if err != nil {
        goto LABEL
    }
}

• Fixes False-positive reports for labeled statements #276

[coveralls]

coverage: 94.644% (+0.03%) from 94.618% — copilot/fix-false-positive-reports into main