Update it.json and fix README.md spelling (#932)

* Update it.json

* Fix spelling and mistakes on it.json

* Fix spelling

README.md

@@ -65,7 +65,7 @@ If you spot a missing phrase while using Obsidian, here's what to do:
 1. Figure out where the language file lives by looking up the language table in the README under the ["Existing languages" section](https://github.com/obsidianmd/obsidian-translations#existing-languages).
 2. Edit the language file, look for the exact English phrase.
 3. Replace it with the appropriate translated phrase.
-4. Submit your changs as a pull request.
+4. Submit your changes as a pull request.
 
 ### Testing translation