Represents a rule to be run on the source file, passing in some
compilation context to aid the rule. (Similar to TreeRule for java/hints).
author: Tor Norbye
getKinds() Get the ElementKinds this rule should run on.
public void
run(RuleContext context, List<Description> result) Run the test on given CompilationUnit and return list of Errors or
warrnings to be shown in the editor.