help: allocate enough space for the descriptions, so we don't crash

We should measure the length of each /translated/ shortcut description,
not of the original English one.

This fixes https://savannah.gnu.org/bugs/?50899.

src/help.c

@@ -470,7 +470,7 @@ void help_init(void)
      * plus one or two \n's. */
     for (f = allfuncs; f != NULL; f = f->next)
 	if (f->menus & currmenu)
-	    allocsize += (16 * MAXCHARLEN) + strlen(f->help) + 2;
+	    allocsize += (16 * MAXCHARLEN) + strlen(_(f->help)) + 2;
 
 #ifndef NANO_TINY
     /* If we're on the main list, we also count the toggle help text.