Problem:  Can't detect angular & mustache filetypes
Solution: Detect *.mustache as Mustache filetype;
          detect *.component.html as html.angular filetype

closes: vim/vim#13594

https://github.com/vim/vim/commit/7bed263c343c62129c5d8f51796895a28db1b312

Some escape sequences (in particular, OSC 52 paste responses) can be
very large, even unbounded in length. These can easily overflow
termkey's internal buffer. In order to process these long sequences,
dynamically grow termkey's internal buffer.

fix(extmark): restore extmarks when completing original text