docs: update 06-accessibility-warnings.md (#8342)

Convert recommended events to use Svelte syntax, and include deprecation warning re https://developer.mozilla.org/en-US/docs/Web/API/Element/keypress_event

site/content/docs/06-accessibility-warnings.md

@@ -55,7 +55,7 @@ Enforce that `autofocus` is not used on elements. Autofocusing elements can caus
 
 ### `a11y-click-events-have-key-events`
 
-Enforce `on:click` is accompanied by at least one of the following: `onKeyUp`, `onKeyDown`, `onKeyPress`. Coding for the keyboard is important for users with physical disabilities who cannot use a mouse, AT compatibility, and screenreader users. 
+Enforce `on:click` is accompanied by at least one of the following: `on:keyup`, `on:keydown`, `on:keypress`. Coding for the keyboard is important for users with physical disabilities who cannot use a mouse, AT compatibility, and screenreader users.
 
 This does not apply for interactive or hidden elements.
 
@@ -64,6 +64,8 @@ This does not apply for interactive or hidden elements.
 <div on:click={() => {}} />
 ```
 
+Note that the `keypress` event is now deprecated, so it is officially recommended to use either the `keyup` or `keydown` event instead, accordingly.
+
 ---
 
 ### `a11y-distracting-elements`