Accessibility: Improve the form labels on the Add New User screen.

On the Multisite - single site "Add New User" screen, some form fields have more
than one label associated with them. Form controls should have at most one
associated label element. If more than one label element is associated to the
control, assistive technologies may not read the appropriate label.

Additionally, labels can be associated to their related form fields either
explicitly (using a `for` attribute referencing the field ID) or implicitly
(using the label to wrap the field). As a best practice, never do both and
prefer explicitly associated labels when possible.

Props Ankit K Gupta.
Fixes #38459.

Built from https://develop.svn.wordpress.org/trunk@39006


git-svn-id: http://core.svn.wordpress.org/trunk@38948 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta1-39005';
+$wp_version = '4.7-beta1-39006';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.