Update docs.html

_layouts/docs.html

@@ -9,7 +9,7 @@ title: Documentation
 
 	<div class="row">
 		<div class="col-lg-3 order-lg-1 mb-5">
-			<a href="{{ site.github-url }}" class="btn btn-block btn-primary mb-5">
+			<a href="{{ site.github_url }}" class="btn btn-block btn-primary mb-5">
 				<i class="fe fe-github mr-2"></i>Browse source code
 			</a>
 
@@ -47,4 +47,4 @@ title: Documentation
 			</div>
 		</div>
 	</div>
-</div>
+</div>