Explain use of he not h in abbreviation test.

Author: DavidSpickett

lldb/test/API/functionalities/abbreviation/TestAbbreviations.py

@@ -20,6 +20,7 @@ def test_command_abbreviations_and_aliases(self):
         self.assertTrue(result.Succeeded())
         self.assertEqual("apropos script", result.GetOutput())
 
+        # "h" could be "help" or "history", "he" can only be "help".
         command_interpreter.ResolveCommand("he", result)
         self.assertTrue(result.Succeeded())
         self.assertEqual("help", result.GetOutput())