Revert links to package in 'packages/react-error-overlay/fixtures/*' (#3902)

packages/react-error-overlay/fixtures/bundle_u.mjs

@@ -17532,7 +17532,7 @@ function formatMessage(message) {
   // Internal stacks are generally useless so we strip them... with the
   // exception of stacks containing `webpack:` because they're normally
   // from user code generated by WebPack. For more information see
-  // https://github.com/facebook/create-react-app/pull/1050
+  // https://github.com/facebookincubator/create-react-app/pull/1050
   message = message.replace(
     /^\s*at\s((?!webpack:).)*:\d+:\d+[\s\)]*(\n|$)/gm,
     ''