Semantic tokens performance improvements (#1342)
Semantic tokens performance improvements (#1342)

* improve clear_highlights performance and robustness

* improve semantic tokens performance by removing regexes

* cache semantic tokens legend

* reduce copying of batched highlights

* add defaults for 3.17 semantic token types

Co-authored-by: Prabir Shrestha <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@prabir.me>
prabirshrestha/vim-lsp,prabirshrestha/vim-lsp