Refreshed existing IT translations, and added a few more (#1391)

Still a long way to go.

Also added a small QoL improvement to the translators instructions.

---------

Co-authored-by: Martin Geisler <martin@geisler.net>

TRANSLATIONS.md

@@ -49,10 +49,17 @@ brew install gettext
 
 ### `dprint`
 
-Install [`dprint`] using their installation instructions.
+Install `dprint` using their
+[installation instructions](https://dprint.dev/install/).
 
 [`dprint`]: https://dprint.dev/
 
+Alternatively, on MacOS with [Homebrew](https://brew.sh/), you can install with:
+
+```shell
+brew install dprint
+```
+
 Ensure you can build the book, and that `mdbook serve` works. For this, follow
 the instructions in the [README](README.md).
 
@@ -173,6 +180,9 @@ output.
 
 ### Building a Translation
 
+Make sure you have gone through the [build setup](./README.md#building) at least
+once.
+
 To use the `po/xx.po` file for your output, run the following command:
 
 ```shell