git-gui: Attach font_ui to all spinbox widgets
git-gui: Attach font_ui to all spinbox widgets

Earlier I missed making sure our spinbox widgets used the same font
as the other widgets around them.  This meant that using a main font
with a size of 20 would make every widget in the options dialog huge,
but the spinboxes would be left with whatever the OS native font is.

Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git