Properly close meta tags (#233)

Author: choldgraf

pydata_sphinx_theme/layout.html

@@ -22,8 +22,8 @@
 {%- endblock %}
 
 {%- block extrahead %}
-    <meta name="viewport" content="width=device-width, initial-scale=1">
-    <meta name="docsearch:language" content="en">
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="docsearch:language" content="en" />
 {%- endblock %}
 
 {# Silence the sidebar's, relbar's #}