Administration: Capitalize "Collapse Main Menu" aria-label string for better consistency.

Follow-up to [59847].

Props swissspidy.
Fixes #59133.



git-svn-id: https://develop.svn.wordpress.org/trunk@59849 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/menu-header.php

@@ -282,7 +282,7 @@ function _wp_menu_output( $menu, $submenu, $submenu_as_parent = true ) {
 	}
 
 	echo '<li id="collapse-menu" class="hide-if-no-js">' .
-		'<button type="button" id="collapse-button" aria-label="' . esc_attr__( 'Collapse Main menu' ) . '" aria-expanded="true">' .
+		'<button type="button" id="collapse-button" aria-label="' . esc_attr__( 'Collapse Main Menu' ) . '" aria-expanded="true">' .
 		'<span class="collapse-button-icon" aria-hidden="true"></span>' .
 		'<span class="collapse-button-label">' . __( 'Collapse Menu' ) . '</span>' .
 		'</button></li>';