📝 Add tscheck note

Author: Schneegans

src/content/docs/contribution-guide.mdx

@@ -126,6 +126,15 @@ You can run the linter by executing the following command:
 npm run lint
 ```
 
+### Type Checking
+
+Kando is written in TypeScript and uses the TypeScript compiler for type checking.
+You can run the type checker by executing the following command:
+
+```bash
+npm run tscheck
+```
+
 ### REUSE Compliance
 
 Kando is compliant with the [REUSE](https://reuse.software/) standard.