bug#12988: isearch fails to persistently indicate case sensitivity

[Kelly Dean]

This is a UI improvement suggestion, not a bug report.
Using 24.2, do: C-s
Then, if you do M-s w, then type a search string, the minibuffer continues to 
indicate word mode while you type your string. That's good.
But if instead you do M-c, the minibuffer just momentarily flashes a case 
sensitivity indicator, then gives no indication of case sensitivity status 
while you type your search string.