add Italian to language lists

comitium.go

@@ -26,6 +26,7 @@ import (
 var supportedLangs = []language.Tag{
 	language.MustParse("en-US"), // default fallback
 	language.MustParse("fr-FR"),
+	language.MustParse("it-IT"),
 }
 
 func main() {

doc/translating.en.md

@@ -2,6 +2,7 @@ comitium is currently translated into:
 
 * English (en-US)
 * French (fr-FR) — thanks to bacardi55
+* Italian (it-IT) — thanks to Stefano Costa
 
 Translations for literally any language not listed above are welcome.