Fix Italian locale plural seconds timeframe

The "seconds" timeframe used "{0} qualche secondo" which produces
nonsensical output like "15 qualche secondo fa" (literally
"15 some second ago"). "qualche secondo" means "a few seconds"
and is appropriate as a standalone phrase, not with a numeric
prefix.

Change to "{0} secondi" which is the correct Italian plural,
producing natural output like "15 secondi fa" ("15 seconds ago").

Author: bysiber

arrow/locales.py

@@ -411,7 +411,7 @@ class ItalianLocale(Locale):
     timeframes = {
         "now": "adesso",
         "second": "un secondo",
-        "seconds": "{0} qualche secondo",
+        "seconds": "{0} secondi",
         "minute": "un minuto",
         "minutes": "{0} minuti",
         "hour": "un'ora",