Improve syntax highlighting performance in JetBrains IDEs

[Derpius]

aka make the plugin actually usable

• We provide all editor integrations through our language server, including syntax highlighting via semantic tokens
• Editors like VSCode request new syntax highlighting frequently while typing, resulting in an editor experience close to a textmate grammar
• However jetbrains editors only seem to request tokens after a few ms of no typing, resulting in a sluggish experience
• We don't want to implement textmate grammars, jetbrains PSI or any other second source of truth to the real lexer/parser

It's likely that there's simply no way to improve this with JetBrains' integration of LSP, but still worth a look

[RedCMD]

a TextMate grammar doesn't need to be extensive
just handle the basics like comments, strings, numerics, brackets etc