Update solution.md

Wouldn't this solution be more flexible?

1-js/10-error-handling/2-custom-errors/1-format-error/solution.md

@@ -2,7 +2,7 @@
 class FormatError extends SyntaxError {
   constructor(message) {
     super(message);
-    this.name = "FormatError";
+    this.name = this.constructor.name;
   }
 }