KT-3161 JetCommenter implementation stub
KT-1545, KT-3161 KDoc lexer & parser
KT-1545, KT-3161 KDoc formatter
Update KetTokens.Comments TokenSet
KDoc lexer refactored (got rid of hacks and separate tokens for words). Fixed bug with isInComment(element) detection.
KDoc wiki links pair matcher and @tags highlighter