chore: fix some comments

CONTRIBUTING.md

@@ -72,14 +72,14 @@ Let's suppose that we are creating the level "King" (which is already created an
 
 To modify or add a new language to the list of supported ones, follow these steps:
 
-1. under `client/src/gamedata` create a new folder with the languge you want to add.
+1. under `client/src/gamedata` create a new folder with the language you want to add.
 2. Copy paste the content you want to translate of any other language into the new directory.
 3. You will need to translate two things:
 
      - `levels` descriptions under `descriptions` subdirectory
      - `strings.json`. For this, only the values of the keys in the json must be translated. Do not translate keys (i.e. `nextLevel`).
 
-4. If you are just modifying an already existing language you can stop here and submit a PR. If you're adding a new language go to the next steps. Translations are mantained by the community but we ask to translate at least the `strings.json` and the `instances.md` and `instances_complete.md` files entirely since those are the most important ones to understand how the game works. Levels which are not translated will default to English in any case.
+4. If you are just modifying an already existing language you can stop here and submit a PR. If you're adding a new language go to the next steps. Translations are maintained by the community but we ask to translate at least the `strings.json` and the `instances.md` and `instances_complete.md` files entirely since those are the most important ones to understand how the game works. Levels which are not translated will default to English in any case.
 5. Add a new key/value in all `strings.json` of all languages for the newly added language. For example, if you're going to add French, add
 
     ```bash