improve docs a little

docs/array/toggle.mdx

@@ -16,7 +16,7 @@ _.toggle(gods, 'ra') // => ['zeus', 'loki']
 _.toggle(gods, 'vishnu') // => ['ra', 'zeus', 'loki', 'vishnu']
 ```
 
-### toggle(list, item, identity)
+### toggle(list, item, toKey)
 
 You can pass an optional `toKey` function to determine the identity of non-primitive values. Helpful when working with more complex data types.
 
@@ -34,7 +34,7 @@ _.toggle(gods, ra, g => g.name) // => [zeus, loki]
 _.toggle(gods, vishnu, g => g.name) // => [ra, zeus, loki, vishnu]
 ```
 
-### toggle(list, item, identity, options)
+### toggle(list, item, toKey, options)
 
 By default, toggle will append the item if it does not exist. If you need to prepend the item instead you can override the `strategy` in the options argument.
 

src/array/toggle.ts

@@ -1,6 +1,19 @@
 /**
- * If the item matching the condition already exists in the list it
- * will be removed. If it does not it will be added.
+ * Either adds or removes an item from an array, based on whether it
+ * already exists in the array. If multiple items match the given
+ * `item`, all matching items will be removed.
+ *
+ * Note that the given `array` is *not mutated*. A copy of the array
+ * is returned with the given item either added or removed.
+ *
+ * - **"toKey" parameter**
+ *   - You may define a `toKey` callback, which is a function that
+ *   converts an item into a value that can be checked for equality.
+ *   When called with the given `item`, an index of -1 will be passed.
+ *
+ * - **"strategy" option**
+ *   - You may define a `strategy` option, which determines where the
+ *   item should be added in the array.
  *
  * @see https://radashi-org.github.io/reference/array/toggle
  * @example
@@ -23,11 +36,7 @@
 export function toggle<T>(
   array: readonly T[],
   item: T,
-  /**
-   * Converts an item of type T item into a value that can be checked
-   * for equality. For an item idx will be -1.
-   */
-  toKey?: null | ((item: T, idx: number) => number | string | symbol),
+  toKey?: ((item: T, idx: number) => number | string | symbol) | null,
   options?: {
     strategy?: 'prepend' | 'append'
   },