Docs: Specify missing `global` variables used in `wp_print_theme_file_tree()`.

The `$relative_file` and `$stylesheet` variables are used in the `wp_print_theme_file_tree()` function but were not noted within the inline documentation.

Props mukesh27, desrosj,
Fixes #43682.
Built from https://develop.svn.wordpress.org/trunk@44477


git-svn-id: http://core.svn.wordpress.org/trunk@44308 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/misc.php

@@ -313,6 +313,10 @@ function wp_make_theme_file_tree( $allowed_files ) {
  * @since 4.9.0
  * @access private
  *
+ * @global string $relative_file Name of the file being edited relative to the
+ *                               theme directory.
+ * @global string $stylesheet    The stylesheet name of the theme being edited.
+ *
  * @param array|string $tree  List of file/folder paths, or filename.
  * @param int          $level The aria-level for the current iteration.
  * @param int          $size  The aria-setsize for the current iteration.

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44476';
+$wp_version = '5.1-alpha-44477';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.