This was initiated in early 6.0, but was reverted back because of ownership changes and some serious issues. Lets try to
finish this job in 6.1.
Where is the difference between issue 154788 (Migrate XML Syntax support to use Lexer) and issue 122438 (XML lexer
migration). Aren't they duplicates?
The difference is that, this issue is the umbrella issue for all lexer migration in XML. See the dependency.