The PR will corerce routes that have a leading slash and throwing a `_doing_it_wrong` notice while ensuring a proper namespace. Fixes #49749. Props TimothyBlynJacobs, skarabeq, afercia. git-svn-id: https://develop.svn.wordpress.org/trunk@47842 602fd350-edb4-49c9-b593-d223f7449a82