Dev: Include closed body and html tags in getTrail

This will allow us to render in Storybook without having issues
with unclosed tags. it also mirrors how html-headelement works
(obscuring the opening of the body and html tags)

Bug: T240062
Bug: T242674
Change-Id: I216a920c68bf3da9de55a75fc53451c68c9cc753

includes/VectorTemplate.php

@@ -112,7 +112,7 @@ class VectorTemplate extends BaseTemplate {
 			// From MWDebug::getHTMLDebugLog (when $wgShowDebug is enabled)
 			'html-debuglog' => $this->get( 'debughtml', '' ),
 			// From BaseTemplate::getTrail (handles bottom JavaScript)
-			'html-printtail' => $this->getTrail(),
+			'html-printtail' => $this->getTrail() . '</body></html>',
 		];
 
 		// TODO: Convert the rest to Mustache

includes/templates/index.mustache

@@ -32,5 +32,3 @@
 {{! html-unported outputs <div id="mw-navigation"> and <div id="footer"> }}
 {{{html-unported}}}
 {{{html-printtail}}}
-</body>
-</html>