Allow each theme to style all aspects of syntax highlighting

Previously, some syntax highlights were controlled in editor.ts,
and shared across all themes.

Co-authored-by: Keith Simmons <keith@zed.dev>

styles/src/utils/snakeCase.ts

@@ -17,7 +17,7 @@ type SnakeCased<Type> = {
 export default function snakeCaseTree<T>(object: T): SnakeCased<T> {
   const snakeObject: any = {};
   for (const key in object) {
-    snakeObject[snakeCase(key)] = snakeCaseValue(object[key]);
+    snakeObject[snakeCase(key, { keepSpecialCharacters: true })] = snakeCaseValue(object[key]);
   }
   return snakeObject;
 }