Editor: Allow the “Add Media” button tooltip to be translated in the …

…Classic block.

In the Classic Editor, the “Add Media” button was outside of the TinyMCE editor. In the Block Editor, the “Add Media” button was moved into the TinyMCE toolbar in the Classic block, but the tooltip was not added to the list of translatable strings. This adds “Add Media” to that list.

The corresponding keyboard shortcut is also specified for the “Add Media” button.

Props afercia.

Merges [44398-44399] to the 5.0 branch.
Fixes #45788.

git-svn-id: https://develop.svn.wordpress.org/branches/5.0@44400 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-editor.php

@@ -1265,6 +1265,7 @@ private static function get_translation() {
 			'Link options'  => __( 'Link options' ), // Tooltip for the 'link options' button in the inline link dialog
 			'Visual' => _x( 'Visual', 'Name for the Visual editor tab' ), // Editor switch tab label
 			'Text' => _x( 'Text', 'Name for the Text editor tab (formerly HTML)' ), // Editor switch tab label
+			'Add Media' => array( __( 'Add Media' ), 'accessM' ), // Tooltip for the 'Add Media' button in the Block Editor Classic block
 
 			// Shortcuts help modal
 			'Keyboard Shortcuts' => array( __( 'Keyboard Shortcuts' ), 'accessH' ),