Issues with ChangeSignatureRefactoring

[sxhya]

• Group search results using refactoring-specific categories, specifically mention usages for which refactoring is not going to work, highlight tail-implicit usages.
• Keep track of typechecking errors, do not modify expressions which contain typechecking errors (retypecheck is not needed, information should be requested from GUI instead).
• Search results window should also be shown when ChangeArgumentExplicitness intention is activated
• Reproduce issues related with backtick notation (check TODOs in code), fix them