feat!: type inference for evaluation types

[jrandolf]

This PR greatly improves the types within Puppeteer:

• Almost everything is auto-deduced.
  • Parameters don't need to be specified in the function. They are deduced from the spread.
  • Return types don't need to be specified. They are deduced from the function. (More on this below)
  • Selections based on tag names correctly deduce element type, similar to TypeScript's mechanism for getElementByTagName.
• [BREAKING CHANGE] We've removed the ability to declare return types in type arguments for the following reasons:
  1. Setting them will indubitably break auto-deduction.
  2. You can just use as ... in TypeScript to coerce the correct type (given it makes sense).
• [BREAKING CHANGE] waitFor is officially gone.

To migrate to these changes, there are only four things you may need to change:

• If you set a return type using the ReturnType type parameter, remove it and use as ... and HandleFor (if necessary).
  ⛔ evaluate<ReturnType>(a: number, b: number) => {...}, a, b)
  ✅ (await evaluate(a, b) => {...}, a, b)) as ReturnType
  ⛔ evaluateHandle<ReturnType>(a: number, b: number) => {...}, a, b)
  ✅ (await evaluateHandle(a, b) => {...}, a, b)) as HandleFor<ReturnType>
• If you set any type parameters in the parameters of an evaluation function, remove them.
  ⛔ evaluate(a: number, b: number) => {...}, a, b)
  ✅ evaluate(a, b) => {...}, a, b)
• If you set any type parameters in the method's declaration, remove them.
  ⛔ evaluate<(a: number, b: number) => void>((a, b) => {...}, a, b)
  ✅ evaluate(a, b) => {...}, a, b)

Fixes: #8485

[stevenwdv]

You could also consider changing ElementHandle<T extends Element> to ElementHandle<T extends ParentNode> to officially support Document and ShadowRoot as well; see my PR #8540

[jrandolf]

@stevenwdv There are plans to handle Nodes! Stay tuned.

[OrKoN]

let's document the breaking part of this PR better? let's perhaps include an example of what worked before and how it should be handled now. E.g., before handle.evaluate<MyCustomType>(() => ..), after handle.evaluate(() => ..) as MyCustomType if I understood it right?

[OrKoN]

By documenting I mean let's include an example into the PR description (and also copy everything from the PR description into the commit message when landing this).

[karlhorky]

Ok, thanks for that. A bit confusing currently unfortunately! (mismatching types / docs). But maybe this will be remedied fairly quickly :)