Docs: Capitalize "ID", when referring to a post ID, term ID, etc. in a more consistent way.

See #49572.

git-svn-id: https://develop.svn.wordpress.org/trunk@48104 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/ms-functions.php

@@ -1213,6 +1213,7 @@ function wpmu_activate_signup( $key ) {
 		 * @param array  $meta     Signup meta data.
 		 */
 		do_action( 'wpmu_activate_user', $user_id, $password, $meta );
+
 		return array(
 			'user_id'  => $user_id,
 			'password' => $password,
@@ -1251,6 +1252,7 @@ function wpmu_activate_signup( $key ) {
 		),
 		array( 'activation_key' => $key )
 	);
+
 	/**
 	 * Fires immediately after a site is activated.
 	 *