wmaker: Do not allocate memory for a temporary string for the Window Shortcut menu
When creating the list of possible shortcut for windows to populate the
window menu, a temporary buffer was allocated to hold that string.
As this allocation participates to memory fragmentation, this patch makes
use of storage on the stack instead which is also faster.
Took opportunity to include the shortcut number (%i) in the string to be
translated, because it is unlikely that adding that number at the end of
the string is right in all languages. Updated french translation because
it is the only one I am confident with.
Signed-off-by: Christophe CURIS <christophe.curis@free.fr>