Don't include trailing \n or <br/> if summary is missing

bot.py

@@ -27,8 +27,10 @@ TEMPLATE_TEXT = (
     "{% elif labels.severity == 'warning' %}"
     "ATTENTION "
     "{% endif %}"
-    "{{ labels.alertname }} {{ labels.instance }}\n"
+    "{{ labels.alertname }} {{ labels.instance }}"
-    "{{ annotations.summary }}"
+    "{% if annotations.summary %}"
+    "\n{{ annotations.summary }}"
+    "{% endif %}"
 )
 
 TEMPLATE_HTML = (
@@ -40,8 +42,11 @@ TEMPLATE_HTML = (
     "<b><font color='orange'>ATTENTION</font></b> "
     "{% endif %}"
     "<b>{{ labels.alertname }}</b> "
-    "{{ labels.instance }}<br/>"
+    "{{ labels.instance }}"
+    "{% if annotations.summary %}"
+    "<br/>"
     "<blockquote>{{ annotations.summary }}</blockquote>"
+    "{% endif %}"
 )