crecord: render chunkpad on Windows (issue6427)

When using Windows wrappers of PDCurses (e.g., windows-curses), the chunkpad
does not render when executing `hg commit -i`. This is due to attempting to
refresh one too many columns of the pad.

Differential Revision: https://phab.mercurial-scm.org/D9267

mercurial/crecord.py

@@ -1250,7 +1250,7 b' class curseschunkselector(object):'
                 self.numstatuslines,
                 0,
                 self.yscreensize - self.numstatuslines,
-                self.xscreensize,
+                self.xscreensize - 1,
             )
         except curses.error:
             pass