feat(eslint-plugin): [prefer-at] docs fixes

Co-authored-by: Josh Goldberg ✨ <git@joshuakgoldberg.com>

packages/eslint-plugin/docs/rules/prefer-at.md

@@ -6,36 +6,23 @@ description: 'Enforce the use of `array.at(-1)` instead of `array[array.length -
 >
 > See **https://typescript-eslint.io/rules/prefer-at** for documentation.
 
-There are two ways to get the last item of the array:
+There are two common ways to get the last item of an array:
 
 - `arr[arr.length - 1]`: getting an item by index calculated relative to the length of the array.
-- `arr.at(-1)`: getting an item by the `at` method. [Docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/at)
+- `arr.at(-1)`: getting an item by the [`at` method](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/at).
 
 `arr.at(-1)` is a cleaner equivalent to `arr[arr.length - 1]`.
 
-This rule supports the following types:
-
-- `string` or `String`
-- `Array`
-- `Int8Array`
-- `Uint8Array`
-- `Uint8ClampedArray`
-- `Int16Array`
-- `Uint16Array`
-- `Int32Array`
-- `Float32Array`
-- `Uint32Array`
-- `Float64Array`
-- `BigInt64Array`
-- `BigUint64Array`
+This rule suggests code use `arr.at(-1)`, as it's cleaner than `arr[arr.length - 1]`.
+It supports built-in array and string types, including integer arrays such as `Int8Array`.
 
 ## Options
 
-```ts
-interface Options {
-  ignoreFunctions?: boolean;
-}
-```
+### `ignoreFunctions`
+
+This option enables ignoring arrays (and other supported types) returned from a function call.
+
+Enable this option if you cannot guarantee that a function called with the same arguments returns the same result.
 
 ## Examples
 
@@ -96,6 +83,4 @@ let b = getArr()[getArr().length - 1];
 
 ## When Not To Use It
 
-If you support a browser that does not match
-[this table](https://caniuse.com/mdn-javascript_builtins_array_at)
-or use `node.js < 16.6.0` and don't include the polyfill
+If you support a runtime environment that doesn't support [ES2022's `.at`](https://caniuse.com/mdn-javascript_builtins_array_at) and don't include a polyfill, you can ignore this rule.

packages/eslint-plugin/src/rules/prefer-at.ts

@@ -31,7 +31,6 @@ export default util.createRule({
               },
             },
             additionalProperties: false,
-            required: ['ignoreFunctions'],
           },
         ],
       },