Update Italian strings

:it: 
I missed that when I reviewed this change....

Yes it is valid.  .PO files allow long texts to be split.  Tools such as POEDIT do this by default.

But the project standard is to not wrap lines.  This is because

1) it creates many more changes, which make the repository larger
2) it makes it difficult to see changes using diff tools.
3) it makes it impossible to search/replace text (for example to fix spelling mistakes in English).

I ask contributors to use "long lines".  It can be done with the command `msgcat --no-wrap XX.po --output=XX.po`

However, when I next update the .PO files from the source code, the format will be corrected automatically.