matrix-synapse nginx template: fix invalid jinja comment syntax

roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2

@@ -105,7 +105,7 @@
 	{% endif %}
 
 	{% if matrix_nginx_proxy_synapse_workers_enabled %}
-		{# Workers redirects BEGIN}
+		{# Workers redirects BEGIN #}
 
 		{% if generic_workers %}
 			# https://github.com/matrix-org/synapse/blob/master/docs/workers.md#synapseappgeneric_worker
@@ -164,7 +164,7 @@
 			}
 			{% endif %}
 		{% endif %}
-		{# Workers redirects END}
+		{# Workers redirects END #}
 	{% endif %}