qmlls: reject invalid rename requests

Reject invalid rename requests in qmlls. Reasons might be:

• C++ defined properties and signals
  • on usages of C++ defined properties
  • on usages of C++ defined signals
  • on usages of C++ defined properties changed signals
  • also for signal handlers on C++ defined signals
  • also for onChanged handlers on C++ defined properties
• C++ defined object
  • Qml Objects defined in C++ cannot be renamed
  • Qml Objects imported from other modules cannot be renamed
    • it would be super unintuitive if a rename renames symbols in a different project/module
• Stuff in comments + keywords
• Invalid names
  • see also https://262.ecma-international.org/7.0/#prod-IdentifierName for valid JS names (WTF? unicode escapes are allowed as identifiers???)
  • see also property documentation for allowed property names at https://doc.qt.io/qt-6/qtqml-syntax-objectattributes.html#property-attributes :

    • Property names must begin with a lower case letter and can only contain letters, numbers and underscores.

    • but the engine does not care and accepts all kinds of weird stuff (ä, $, unicode escapes of allowed characters)