feat(shared/codeHighlight): add Swift syntax highlighting support

Add support for Swift language highlighting in the code highlighter
component. This enables proper syntax highlighting for Swift code by
importing the swift language module from @codemirror/legacy-modes and
adding a parser definition for files with the 'swift' extension.

Author: jimeh

packages/shared/src/lib/codeHighlight.ts

@@ -22,6 +22,7 @@ import { HighlightStyle, StreamLanguage } from '@codemirror/language';
 import { commonLisp } from '@codemirror/legacy-modes/mode/commonlisp';
 import { lua } from '@codemirror/legacy-modes/mode/lua';
 import { ruby } from '@codemirror/legacy-modes/mode/ruby';
+import { swift } from '@codemirror/legacy-modes/mode/swift';
 import { toml } from '@codemirror/legacy-modes/mode/toml';
 import { NodeType, Tree, Parser } from '@lezer/common';
 import { tags, highlightTree } from '@lezer/highlight';
@@ -189,6 +190,9 @@ export function parserFromFilename(filename: string): Parser | null {
 			// highlighting svelte with js + jsx works much better than the above
 			return javascript({ typescript: true, jsx: true }).language.parser;
 
+		case 'swift':
+			return StreamLanguage.define(swift).parser;
+
 		case 'vue':
 			return vue().language.parser;