Twenty Fifteen: Ensure the `<nav>` elements in widgets do not affect bottom margin.

Follow-up to [49208].

Props sabernhardt.
See #51445.
Built from https://develop.svn.wordpress.org/trunk@49469


git-svn-id: http://core.svn.wordpress.org/trunk@49228 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-content/themes/twentyfifteen/style.css

@@ -1398,7 +1398,8 @@ img.aligncenter {
 	text-transform: uppercase;
 }
 
-.widget > :last-child {
+.widget > :last-child,
+.widget > nav > :last-child {
 	margin-bottom: 0;
 }
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-beta2-49452';
+$wp_version = '5.6-beta2-49469';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.