update readme: fix typo.
@@ -93,7 +93,7 @@ Also:
- <kbd>Ctrl</kbd> + <kbd>F</kbd> (i.e. EOF) to exit; you can also use the `exit` command.
- <kbd>Ctrl</kbd> + <kbd>L</kbd> to clear screen; you can also use the `clear` command.
-- <kbd>Ctrl</kbd> + <kbd>X</kbd> <kbd>Ctrl</kbd> + <kbd>X</kbd> to open an editor
+- <kbd>Ctrl</kbd> + <kbd>X</kbd> <kbd>Ctrl</kbd> + <kbd>E</kbd> to open an editor
to edit command, or <kbd>V</kbd> in vi-mode.
## Development
