lua-language-server marks globals with the `global` token modifier, but
the editor dropped it, so a global variable looked like a local unless
rainbow highlighting was on. The modifier now sets `cm-sem-global`, drawn
in a new Language Defaults › Identifiers › Global variable colour
(`--syn-global`): library globals keep the predefined colour and calls the
function-call colour. Imported IntelliJ themes and .icls schemes take it
from DEFAULT_GLOBAL_VARIABLE. Built-in schemes default it to the local
variable colour (IntelliJ's fallback for the key), so they look as before
until a scheme sets it.
Fixes#1370
The Color Scheme page only offered built-in schemes, so a scheme from another IDE could not be used.
Import reads .icls files into named custom schemes in user settings, reports applied and skipped values, and rejects malformed files. Export writes the current scheme, replacing an existing file, and custom schemes can be deleted. Colours are validated before reaching a stylesheet, and project settings cannot define schemes. The Appearance selector and Quick Switch list custom schemes too.
Fixes#513
l0ng-ai