Re-phrase "copy-paste-able code" guideline

guidelines/markdown.md

         >
         > and *everything* will work.
 
- *  Try for copy/paste-able code i.e. avoid prompt char (`$`, `%`, `%`)
-    unless you are pasting *output*.  To convey the need of root privilege,
-    mention that in surrounding text or use *sudo*.
-
+ *  Unless you are pasting *output*, avoid prompt char (`$`, `%`, `%`)
+    in order to provide code that can be copied.  To convey the need of
+    root privilege, mention that in surrounding text or use *sudo*.