Clarify comment related to CAPTCHA modules

- Clarify when module
  json_format_actions_support.rb
  is used or not

app/controllers/concerns/spammable_actions/captcha_check/json_format_actions_support.rb

@@ -4,6 +4,12 @@
 # In other words, forms handled by actions which use a `respond_to` of `format.js` or `format.json`.
 #
 # For example, for all Javascript based form submissions and Vue components which use Apollo and Axios
+# which are directly handled by a controller other than `GraphqlController`. For example, issue
+# update currently uses this module.
+#
+# However, requests which directly hit `GraphqlController` will not use this module - the
+# `Mutations::SpamProtection` module handles those requests (for example, snippet create/update
+# requests)
 #
 # If the request is handled by actions via `format.html`, then the corresponding module which
 # supports HTML format should be used instead.