Save a history of `rg` commands, add this feature to the main menu.

When `rg_wrapper` is run, we can store on a buffer the commands the user has input. Add another option to main menu mentioned on #1 to show the history of commands so, he can repeat a previous command without typing it again.

Start by locating the command-input loop and main-menu entry point in rg_wrapper. Trace how user commands are currently read, then determine where an in-memory history can be maintained and how the new menu option should expose it. Done means users can view saved commands and repeat one without retyping it.

Written by the indexing model from the issue text.