feat(types): add types for $eval (#6135)

This pulls in the types (based on the DefinitelyTyped repo) for
`page.$eval` (and the `$eval` method on other classes). The `$eval`
method is quite hard to type due to the way we wrap and unwrap
ElementHandles that are passed to / returned from the `pageFunction`
that users provide.

Longer term we can improve the types by providing type overloads as
DefinitelyTyped does but I've deferred that for now (see the `TODO` in
the code for more details).

new-docs/puppeteer.jshandle.evaluatehandle.md

@@ -9,7 +9,7 @@ This method passes this handle as the first argument to `pageFunction`<!-- -->.
 <b>Signature:</b>
 
 ```typescript
-evaluateHandle<HandleType extends JSHandle | ElementHandle = JSHandle>(pageFunction: EvaluateHandleFn, ...args: SerializableOrJSHandle[]): Promise<HandleType>;
+evaluateHandle<HandleType extends JSHandle = JSHandle>(pageFunction: EvaluateHandleFn, ...args: SerializableOrJSHandle[]): Promise<HandleType>;
 ```
 
 ## Parameters