add entity methods creator back to docs

Author: EskiMojo14

docs/usage/custom-slice-creators.mdx

@@ -324,6 +324,105 @@ reducers: (create) => {
 
 :::
 
+##### `create.entityMethods` (`entityMethodsCreator`)
+
+Creates a set of reducers for managing a normalized entity state, based on a provided [adapter](./createEntityAdapter).
+
+```ts
+import {
+  createEntityAdapter,
+  buildCreateSlice,
+  entityMethodsCreator,
+} from '@reduxjs/toolkit'
+
+const createAppSlice = buildCreateSlice({
+  creators: { entityMethods: entityMethodsCreator },
+})
+
+interface Post {
+  id: string
+  text: string
+}
+
+const postsAdapter = createEntityAdapter<Post>()
+
+const postsSlice = createAppSlice({
+  name: 'posts',
+  initialState: postsAdapter.getInitialState(),
+  reducers: (create) => ({
+    ...create.entityMethods(postsAdapter),
+  }),
+})
+
+export const { setOne, upsertMany, removeAll, ...etc } = postsSlice.actions
+```
+
+:::caution
+
+Because this creator returns an object of multiple reducer definitions, it should be spread into the final object returned by the `reducers` callback.
+
+:::
+
+**Parameters**
+
+- **adapter** The [adapter](../api/createEntityAdapter) to use.
+- **config** The configuration object. (optional)
+
+The configuration object can contain some of the following options:
+
+**`selectEntityState`**
+
+A selector to retrieve the entity state from the slice state. Defaults to `state => state`, but should be provided if the entity state is nested.
+
+```ts no-transpile
+const postsSlice = createAppSlice({
+  name: 'posts',
+  initialState: { posts: postsAdapter.getInitialState() },
+  reducers: (create) => ({
+    ...create.entityMethods(postsAdapter, {
+      selectEntityState: (state) => state.posts,
+    }),
+  }),
+})
+```
+
+**`name`, `pluralName`**
+
+It's often desirable to modify the reducer names to be specific to the data type being used. These options allow you to do that simply.
+
+```ts no-transpile
+const postsSlice = createAppSlice({
+  name: 'posts',
+  initialState: postsAdapter.getInitialState(),
+  reducers: (create) => ({
+    ...create.entityMethods(postsAdapter, {
+      name: 'post',
+    }),
+  }),
+})
+
+const { addOnePost, upsertManyPosts, removeAllPosts, ...etc } =
+  postsSlice.actions
+```
+
+`pluralName` defaults to `name + 's'`, but can be provided if this isn't desired.
+
+```ts no-transpile
+const gooseSlice = createAppSlice({
+  name: 'geese',
+  initialState: gooseAdapter.getInitialState(),
+  reducers: (create) => ({
+    ...create.entityMethods(gooseAdapter, {
+      name: 'goose',
+      pluralName: 'geese',
+    }),
+  }),
+})
+
+const { addOneGoose, upsertManyGeese, removeAllGeese, ...etc } =
+  gooseSlice.actions
+```
+
 ## Writing your own creators
 
 In version v2.3.0, we introduced a system for including your own creators.
@@ -338,7 +437,7 @@ For example, the `create.preparedReducer` creator uses a definition that looks l
 
 The callback form of `reducers` should return an object of reducer definitions, by calling creators and nesting the result of each under a key.
 
-```js no-transpile
+```js
 reducers: (create) => ({
   addTodo: create.preparedReducer(
     (todo) => ({ payload: { id: nanoid(), ...todo } }),