fix typo, add comment

common/lib/xmodule/xmodule/capa_module.py

@@ -414,12 +414,14 @@ class CapaModule(XModule):
         elif self.show_answer == "never":
             return False
         elif self.system.user_is_staff:
-            # This i after the 'never' check because admins can see the answer
+            # This is after the 'never' check because admins can see the answer
             # unless the problem explicitly prevents it
             return True
         elif self.show_answer == 'attempted':
             return self.attempts > 0
         elif self.show_answer == 'answered':
+            # NOTE: this is slightly different from 'attempted' -- resetting the problems
+            # makes lcp.done False, but leaves attempts unchanged.
             return self.lcp.done
         elif self.show_answer == 'closed':
             return self.closed()