docs: capitalize Custom Hook references

Author: Harsherr

src/content/reference/react/useTransition.md

@@ -312,7 +312,7 @@ For common use cases, React provides built-in abstractions such as:
 - [`<form>` actions](/reference/react-dom/components/form)
 - [Server Functions](/reference/rsc/server-functions)
 
-These solutions handle request ordering for you. When using Transitions to build your own custom hooks or libraries that manage async state transitions, you have greater control over the request ordering, but you must handle it yourself.
+These solutions handle request ordering for you. When using Transitions to build your own custom Hooks or libraries that manage async state transitions, you have greater control over the request ordering, but you must handle it yourself.
 
 <Solution />
 

src/content/reference/rules/components-and-hooks-must-be-pure.md

@@ -291,7 +291,7 @@ function useIconStyle(icon) {
 }
 ```
 
-One important principle in React is _local reasoning_: the ability to understand what a component or hook does by looking at its code in isolation. Hooks should be treated like "black boxes" when they are called. For example, a custom hook might have used its arguments as dependencies to memoize values inside it:
+One important principle in React is _local reasoning_: the ability to understand what a component or hook does by looking at its code in isolation. Hooks should be treated like "black boxes" when they are called. For example, a custom Hook might have used its arguments as dependencies to memoize values inside it:
 
 ```js {4}
 function useIconStyle(icon) {
@@ -307,7 +307,7 @@ function useIconStyle(icon) {
 }
 ```
 
-If you were to mutate the Hook's arguments, the custom hook's memoization will become incorrect,  so it's important to avoid doing that.
+If you were to mutate the Hook's arguments, the custom Hook's memoization will become incorrect,  so it's important to avoid doing that.
 
 ```js {4}
 style = useIconStyle(icon);         // `style` is memoized based on `icon`