Simplify JSON trailing comment regular expression

Not a huge change, but when it comes to regular expressions, every bit
of simplification helps—at least when it comes to readability, if not
performance.

lib/index.js

@@ -214,7 +214,7 @@ export function stripJsonComments(jsonStr) {
     }
     result += curChar
   }
-  return result.replaceAll(/,(\s*)([\]}])/g, ' $1$2')
+  return result.replaceAll(/,(\s*[\]}])/g, ' $1')
 }
 
 /**