use mocha and tsx to run tests

readme.md

@@ -20,13 +20,13 @@ Each kata has a `tests.ts` file.
 To run the tests for a specific kata, run the following command:
 
 ```bash
-npx mocha -r ts-node/register path/to/specific/tests.ts
+npx mocha --import=tsx path/to/specific/tests.ts
 ```
 
 If you're in the right folder:
 
 ```bash
-npx mocha -r ts-node/register tests.ts
+npx mocha --import=tsx ./tests.ts
 ```
 
 ## Adding a new kata