Merge pull request #1279 from alphagov/placeholders-in-contact-block

Enable placeholders in letter contact block

app/templates/views/service-settings/set-letter-contact-block.html

@@ -18,7 +18,8 @@
         label='How should users contact your service?<br>This applies to all the letters you send.'|safe,
         hint='10 lines maximum',
         width='1-1',
-        rows=10
+        rows=10,
+        highlight_tags=True
       ) }}
       {{ page_footer(
         'Save',