Further improvements of documentation comment and hover feature

Ideas to further improve the current state of documentation comment feature:

• Mark only the given tags when problems are detected
• Deprecated nodes should be highlighted in the hover info
• Inherited class members should be highlighted in the hover info
• Overridden class functions should be highlighted in the hover info
• Doc comments of class functions should be parsed
• Handle parse errors
• Do not generate @member tag for inherited class members if they are not overriding parent functions
• For inherited class members, get @member info from parent class's comment
• class, record and union member list is not shown if document comment is missing