docs: add useUpsert to readme

README.md

@@ -131,7 +131,7 @@
   - [`useStateList`](./docs/useStateList.md) — circularly iterates over an array. [![][img-demo]](https://codesandbox.io/s/bold-dewdney-pjzkd)
   - [`useToggle` and `useBoolean`](./docs/useToggle.md) — tracks state of a boolean. [![][img-demo]](https://codesandbox.io/s/focused-sammet-brw2d)
   - [`useCounter` and `useNumber`](./docs/useCounter.md) — tracks state of a number. [![][img-demo]](https://streamich.github.io/react-use/?path=/story/state-usecounter--demo)
-  - [`useList`](./docs/useList.md) — tracks state of an array. [![][img-demo]](https://codesandbox.io/s/wonderful-mahavira-1sm0w)
+  - [`useList`](./docs/useList.md) and [`useUpsert`](./docs/useUpsert.md) — tracks state of an array. [![][img-demo]](https://codesandbox.io/s/wonderful-mahavira-1sm0w)
   - [`useMap`](./docs/useMap.md) — tracks state of an object. [![][img-demo]](https://codesandbox.io/s/quirky-dewdney-gi161)
 
 

docs/useList.md

@@ -25,3 +25,7 @@ const Demo = () => {
   );
 };
 ```
+
+## Related hooks
+
+- [useUpsert](./useUpsert.md)

docs/useUpsert.md

@@ -1,6 +1,7 @@
 # `useUpsert`
 
-Superset of `useList`. Provides an additional method to upsert (update or insert) an element into the list. 
+Superset of [`useList`](./useList.md). Provides an additional method to upsert (update or insert) an element into the list.
+
 ## Usage
 
 ```jsx
@@ -26,3 +27,7 @@ const Demo = () => {
   );
 };
 ```
+
+## Related hooks
+
+- [useList](./useList.md)