make SvelteComponentDev typings more forgiving (#5937)

Add `$$events_def` and `$$slot_def` so that users can do
```
let el: SvelteComponent;
<SomeComponent bind:this={el} />
```
without type errors.

Author: dummdidumm

CHANGELOG.md

@@ -5,6 +5,7 @@
 * Throw a parser error for `class:` directives with an empty class name ([#5858](https://github.com/sveltejs/svelte/issues/5858))
 * Fix type inference for derived stores ([#5935](https://github.com/sveltejs/svelte/pull/5935))
 * Make parameters of built-in animations and transitions optional ([#5936](https://github.com/sveltejs/svelte/pull/5936))
+* Make `SvelteComponentDev` typings more forgiving ([#5937](https://github.com/sveltejs/svelte/pull/5937))
 
 ## 3.32.0
 

src/runtime/internal/dev.ts

@@ -115,6 +115,20 @@ export class SvelteComponentDev extends SvelteComponent {
 	 * ### DO NOT USE!
 	 */
 	$$prop_def: Props;
+	/**
+	 * @private
+	 * For type checking capabilities only.
+	 * Does not exist at runtime.
+	 * ### DO NOT USE!
+	 */
+	$$events_def: any;
+	/**
+	 * @private
+	 * For type checking capabilities only.
+	 * Does not exist at runtime.
+	 * ### DO NOT USE!
+	 */
+	$$slot_def: any;
 
 	constructor(options: {
 		target: Element;