fix: fine-grained-reactivity typos (#1649)

Fixes two typos on the fine-grained-reactivity page:

- `This is particularly useful for to make sure` -> `This is particularly useful for making sure`
- `its'` -> `its`

Author: austin-weeks

src/routes/(1)advanced-concepts/(0)fine-grained-reactivity.mdx

@@ -295,11 +295,11 @@ As a result, this `count` signal will not add the callback as a subscriber which
 
 While the basic reactivity system is synchronous, frameworks like Solid offer more advanced features to handle asynchronous scenarios.
 For example, the `on` function provides a way to manually specify the dependencies of an effect.
-This is particularly useful for to make sure asynchronous operations are correctly tied into the reactive system.
+This is particularly useful for making sure asynchronous operations are correctly tied into the reactive system.
 
 Solid also introduces the concept of resources for managing asynchronous operations.
 Resources are specialized reactive primitives that convert the asynchronicity of operations like network requests into synchronicity, embedding the results within a signal.
-The system can then track asynchronous operations and their state, keeping the UI up-to-date when the operation completes or its' state changes.
+The system can then track asynchronous operations and their state, keeping the UI up-to-date when the operation completes or its state changes.
 
 Using resources in Solid can assist in complex scenarios when multiple asynchronous operations are involved and the completion may affect different parts of the reactive system.
 By integrating resources into the system, you can ensure that dependencies are correctly tracked and that the UI remains consistent with the underlying asynchronous data.