Fix non-functional Sphinx link

A space character was missing

Author: marcelm

Diff for: doc/_templates/layout.html

@@ -238,7 +238,7 @@ <h3>{{ _('Navigation') }}</h3>
     {%- endif %}
     {%- if show_sphinx %}
 	{% trans sphinx_version=sphinx_version|e %}Created using
-	<ahref="http://sphinx-doc.org/">Sphinx</a> {{ sphinx_version }}.{% endtrans %}
+	<a href="http://sphinx-doc.org/">Sphinx</a> {{ sphinx_version }}.{% endtrans %}
     {%- endif %}
     {%- if sha %}
 	Doc version {{ sha }}.