git-gui: Added Options... menu item to end of diff context menu.

Since the font name can only be chosen from within the options dialog
giving the user fast access to this dialog from within a context menu
that already talks about increasing and decreasing the font size may
help users to locate the font name setting as well.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

git-gui

@@ -2068,7 +2068,7 @@ $ui_index tag conf in_diff -font font_uibold
 $ui_other tag conf in_diff -font font_uibold
 
 # -- Diff and Commit Area
-frame .vpane.lower -height 400 -width 400
+frame .vpane.lower -height 300 -width 400
 frame .vpane.lower.commarea
 frame .vpane.lower.diff -relief sunken -borderwidth 1
 pack .vpane.lower.commarea -side top -fill x
@@ -2254,6 +2254,9 @@ $ui_diff.ctxm add command -label "Decrease Font Size" \
 $ui_diff.ctxm add command -label "Increase Font Size" \
 	-font font_ui \
 	-command {incr_font_size font_diff 1}
+$ui_diff.ctxm add command -label {Options...} \
+	-font font_ui \
+	-command do_options
 bind_button3 $ui_diff "tk_popup $ui_diff.ctxm %X %Y"
 
 # -- Status Bar