Themes: add "description" key to i18n schema

Add "description" key to the theme.json i18n schema.

Follows r56041.
Fixes #61543.
Props ramonopoly, oandregal.

Built from https://develop.svn.wordpress.org/trunk@58632


git-svn-id: http://core.svn.wordpress.org/trunk@58061 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/theme-i18n.json

@@ -1,5 +1,6 @@
 {
 	"title": "Style variation name",
+	"description": "Style variation description",
 	"settings": {
 		"typography": {
 				"fontSizes": [

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58631';
+$wp_version = '6.7-alpha-58632';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.