F5/F6 rename functionality

[Marcin Skoczylas]

I believe that a rename file was F6 not S-F6 in ancient versions of MC 
for a reason. It's a bad thing to change something without making a 
research about the impact. Not everybody has a possibility to just press 
Shift+F6 and MC and also programs such as a VI text editor were designed 
to run flawlessly on many strange terminals. ESC 6 did work as a rename 
in the past because the file name was shown and editable. Somebody 
decided to change this however, without thinking about further results 
of such change: now ESC 6 does not provide me simple/fast rename 
functionality and ESC shift+6 does not work for me either. Maybe just 
simple solution is to add a key shortcut ESC shift+6 to work as S-F6.

greetings,
Marcin