Update it.po

[albanobattistella]

Pull request summary:

• What does the pull request do? Why is it necessary?

UI related changes:

• Add any screenshots of UI related changes here

Build system related changes:

• Does the pull request cause any new dependencies to be required?
• Have any new dependencies, quirks, options or makefile targets been documented?

Related issues / pull requests:

• If the pull request requires another pull request to be merged first, please make note of this in the summary and mark the pull request as WIP
• If the pull request is designed to fix an issue, tag it at the end of the pull request
• For example, add Fixes #1 as the last line

[stuarthayhurst]

Thanks :)