docs: Broken URL

Change broken URL: `docs.nestjs/com`.
It should probably be:
```html
<a href="https://docs.nestjs.com/fundamentals/module-ref#resolving-scoped-providers">here</a>
```

Author: ewh

content/fundamentals/unit-testing.md

@@ -304,7 +304,7 @@ The compiled module has several useful methods, as described in the following ta
 
 [Request-scoped](/fundamentals/injection-scopes) providers are created uniquely for each incoming **request**. The instance is garbage-collected after the request has completed processing. This poses a problem, because we can't access a dependency injection sub-tree generated specifically for a tested request.
 
-We know (based on the sections above) that the `resolve()` method can be used to retrieve a dynamically instantiated class. Also, as described <a href="https://docs.nestjs/com/fundamentals/module-ref#resolving-scoped-providers">here</a>, we know we can pass a unique context identifier to control the lifecycle of a DI container sub-tree. How do we leverage this in a testing context?
+We know (based on the sections above) that the `resolve()` method can be used to retrieve a dynamically instantiated class. Also, as described <a href="https://docs.nestjs.com/fundamentals/module-ref#resolving-scoped-providers">here</a>, we know we can pass a unique context identifier to control the lifecycle of a DI container sub-tree. How do we leverage this in a testing context?
 
 The strategy is to generate a context identifier beforehand and force Nest to use this particular ID to create a sub-tree for all incoming requests. In this way we'll be able to retrieve instances created for a tested request.