Improve issue check-list

Make definition of "support request" clearer.
Warn about quoting logs to prevent them being interpreted as Markdown.

.github/ISSUE_TEMPLATE.md

@@ -1,12 +1,16 @@
 <!--
-The issue tracker is a tool to address bugs.
+The issue tracker is a tool to address bugs abd bew feature requests.
+
 For support questions, please use: https://github.com/kivy/buildozer#support
 
+** If you are asking about an error messsage you don't understand, or how to use Kivy to implement a feature, do not post it here. **
+
 Before opening a new issue, make sure you do the following:
     * check that your issue isn't already filed: https://github.com/kivy/buildozer/issues
     * prepare a short, runnable example that reproduces the issue
     * make sure to have `log_level = 2` in your `buildozer.spec`
     * reproduce the problem with the latest development version of Kivy
+    * check the appearance with the preview button. Make sure there are triple quotes around your logs and buildozer.spec
     * double-check that the issue is indeed a bug and not a support request
 -->