Update plus code input description for clarity in new event template

Author: SableRaf

.github/ISSUE_TEMPLATE/new-event.yml

@@ -22,10 +22,14 @@ body:
     id: plus_code
     attributes:
       label: Map placement
-      description: Find or verify the plus code for your event location at https://plus.codes. If your event is online or the location is still to be determined, use a general location such as the city center or a relevant landmark. The plus code should be 10 or 11 characters long (e.g. 9F4MFCCM+JF).
-      placeholder: 9F4MFCCM+JF
+      description: Find or verify the plus code for your event location at https://plus.codes. The code should be 10 or 11 characters long (e.g. 9F4MFCCM+JF).
+      placeholder: XXXXXXXX+XX
     validations:
       required: true
+  - type: markdown
+    attributes:
+      value: |
+        If your event is online or the location is still to be determined, use a general location such as the city center or a relevant landmark. 
   - type: dropdown
     id: format
     attributes: