Posts, Post Types: Introduce edit_post_{$post->post_type} hook.

The hook fires before the general `edit_post` hook and has the same parameters.

It also complements the `save_post_{$post->post_type}` hook added in [25050].

Props Mte90, garrett-eclipse.
Fixes #34706.

git-svn-id: https://develop.svn.wordpress.org/trunk@43535 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-customize-manager.php

@@ -2988,6 +2988,9 @@ final class WP_Customize_Manager {
 		$post->post_status = $new_status;
 		wp_transition_post_status( $new_status, $old_status, $post );
 
+		/** This action is documented in wp-includes/post.php */
+		do_action( "edit_post_{$post->post_type}", $post->ID, $post );
+
 		/** This action is documented in wp-includes/post.php */
 		do_action( 'edit_post', $post->ID, $post );