Drop confusing comment

Summary:
Just removing a comment

As per f8d6b97140 (r28569388)

While the comment was more to notify about this in general, I suppose it doesn't matter.

Reviewed By: rafeca

Differential Revision: D7685277

fbshipit-source-id: 2d526aeccc2e89b42ae25cbce21af5fe96f1348d

jest/preprocessor.js

@@ -62,7 +62,6 @@ module.exports = {
         [
           require('@babel/plugin-proposal-class-properties'),
           // use `this.foo = bar` instead of `this.defineProperty('foo', ...)`
-          // (Makes the properties enumerable)
           {loose: true},
         ],
         [require('@babel/plugin-transform-computed-properties')],