update description of autojump command

This closes #570

bin/autojump

@@ -95,7 +95,7 @@ def set_defaults():
 
 def parse_arguments():
     parser = ArgumentParser(
-        description='Automatically jump to directory passed as an argument.',
+        description='Print first matching directory passed as an argument to stdout.',
         epilog='Please see autojump(1) man pages for full documentation.',
     )
     parser.add_argument(