change to contact us to be consistent with other texts

Signed-off-by: Toshaan Bharvani <toshaan@vantosh.com>

themes/openpowerfoundation/layouts/partials/navbar.html

@@ -64,7 +64,7 @@
 						{{ end }}
 					{{ end }}
 				{{ end }}
-				<li class="header__menu-item"><a href="{{ "/contact/" | relURL }}">Contact</a></li>
+				<li class="header__menu-item"><a href="{{ "/contact/" | relURL }}">Contact Us</a></li>
 			</ul>
 			<div class="mobile-view-social-join pt-3">
 				<div class="header__contact-btn join-us-button mobile-view py-4">