git-gui i18n: internationalize use of colon punctuation

Internationalize use of colon punctuation ':' in options window, windows
titles, database statistics window. Some languages might use a different
style, for instance French uses "User Name :" (space before colon).

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>

lib/branch_delete.tcl

@@ -128,7 +128,7 @@ method _delete {} {
 		set b [lindex $i 0]
 		set o [lindex $i 1]
 		if {[catch {git branch -D $b} err]} {
-			append failed " - $b: $err\n"
+			append failed [mc " - %s:" $b] " $err\n"
 		}
 	}