Improve doc comment

Author: sandersn

src/compiler/checker.ts

@@ -6846,9 +6846,10 @@ namespace ts {
  return members;
  }
 
- /** Mark an object literal as exempt from the excess properties check.
- * Recursively mark object literal members as exempt.
- * Leave signatures alone since they are not subject to the check.
+ /**
+ * If the the provided object literal is subject to the excess properties check,
+ * create a new that is exempt. Recursively mark object literal members as exempt.
+ * Leave signatures alone since they are not subject to the check.
  */
  function getRegularTypeOfObjectLiteral(type: Type): Type {
  if (!(type.flags & TypeFlags.FreshObjectLiteral)) {