Support overriding the language of the template block

[zealot128]

Follow up from #2

• I added a test to support the case - If any attribute is given to the template tag, handle the inner content as "raw_text"
  • I found that searching for attributes is the easiest case. I hope there is no other reason to pass any other arguments to the template tag, I have never seen it in the wild.
• I needed to add another clause in scanner.cc to handle raw_text of template similar like script/style

I am not sure about the other changes in the C source files. They are from tree-sitter generate. Let me know if this is clutter or what should be changed!

[bjesus]

Would be great to be able to have Pug syntax highlighting inside Vue files!