git-gui: Optimize encoding name resolution using a lookup table.

Encoding menu construction does almost a hundred of encoding
resolutions, which with the old implementation led to a
small but noticeable delay.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Tested-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
1 file changed