Some sections of code that prompt the user for a string of input were
calling get_str() with cw (the player-visible screen containing the
map), which caused whatever the player typed to get printed starting at
cw's idea of the cursor position, which was usually the Rogue's @-sign.
This corrupted the map.
The problem has been fixed by passing msgw (the message line at the top
of the screen) to get_str(), so the player's typing appears where msgw
thinks the cursor should be, which is in the sensible place right after
the prompt. Some other get_str() invocations which used hw or stdscr
have been left unmodified.
