tidy up tsconfig

Author: donmccurdy

packages/engine/tsconfig.json

@@ -1,17 +1,20 @@
 {
   "include": ["Source/**/*.js"],
   "compilerOptions": {
-    // module configuration
+    // Module configuration.
     "moduleResolution": "bundler",
     "module": "ES2022",
     "target": "ES2022",
 
-    // i/o
+    // I/O.
     "noEmit": true,
     "allowJs": true,
+
+    // Disabled by default. Individual JS files may opt-in to type checking
+    // by including a `// @ts-check` comment at top of file.
     "checkJs": false,
 
-    // TODO(donmccurdy): Explain or remove.
+    // TODO(donmccurdy): Keep or remove?
     "skipLibCheck": true
   }
 }