docs: custom fixtures in cucumber style steps

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## dev
+* support custom fixtures in cucumber-style steps
+
 ## 5.4.0
 * i18n: Generate scenario outlines correctly [#60](https://github.com/vitalets/playwright-bdd/issues/60).
 * Check for duplicate fixture names [#52](https://github.com/vitalets/playwright-bdd/issues/52)

docs/writing-steps.md

@@ -272,3 +272,33 @@ setWorldConstructor(CustomWorld);
 > Consider asynchronous setup and teardown of `BddWorld` using `init()` / `destroy()` methods.
 
 See [full example of Cucumber-style](https://github.com/vitalets/playwright-bdd/tree/main/examples/cucumber-style).
+
+### Custom fixtures
+Along with built-in fixtures you can use any custom fixture in cucumber-style steps.
+To get fixture call `this.useFixture(fixtureName)` method inside step body.
+
+For example:
+```js
+When('I open todo page', async function () {
+  const todoPage = this.useFixture('todoPage');
+  await todoPage.open();
+});
+```
+
+For **TypeScript** you can pass `typeof test` as a second generic parameter to `BddWorld`:
+
+```ts
+type MyWorld = BddWorld<object, typeof test>;
+
+When<MyWorld>('I open todo page', async function () {
+  const todoPage = this.useFixture('todoPage');
+  await todoPage.open();
+});
+```
+
+> Please note that **you can only pass static strings** to `this.useFixture()`. Function body is analyzed to find used fixtures. Below **will not work**:
+```ts
+// will not work!
+const fixtureName = 'todoPage';
+const todoPage = this.useFixture(fixtureName);
+```