fix(gotmpl): cleanup tree-sitter

[qvalentin]

Hi, thanks for the nice plugin.

I help upstreaming https://github.com/ngalaiko/tree-sitter-go-template to https://github.com/nvim-treesitter/nvim-treesitter and think this should be updated in this plugin.

Changes:

• Update docs to install gotmpl tree-sitter directly from nvim-treesitter
• remove queries/gotmpl/highlights.scm since this is already in nvim-treesitter
• update injections, (text) @yaml has no effect I guess?
• To be discussed: the injections file currently sets up html and javascript injections, which is kind of weird, since it means two tree-sitter parsers are used for the same text at the same time
  • this also means if the user want to template yaml the html and js parser will be active for those files

[ray-x]

Thanks!