Mark entity safe and reinstall escape -- make title display right

Change to explicitly mark the string entity — as safe and
reinstate escaping of doctitle.

If this worked in the past maybe auto-escaping wasn't turned on. If it
is in the newer versions of sphinx's jinja |safe is needed now (and |e
isn't, but it doesn't seem to cause double escaping so....).

Author: rouilj

doc/_templates/layout.html

@@ -87,7 +87,7 @@ <h3>{{ _('Quick search') }}</h3>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     {{ metatags }}
     {%- if builder != 'htmlhelp' %}
-      {%- set titlesuffix = " &mdash; " + docstitle %}
+      {%- set titlesuffix = " &mdash; "|safe + docstitle|e %}
     {%- endif %}
     <title>{{ title|striptags }}{{ titlesuffix }}</title>
     {%- if builder == 'web' %}