1. Fixtures defined in test.extend() can now have `{ option: true }` configuration that makes them overridable in the config. Options support all other properties of fixtures - value/function, scope, auto.
```
const test = base.extend<MyOptions>({
foo: ['default', { option: true }],
});
```
2. test.declare() and project.define are removed.
3. project.use applies overrides to default option values and nothing else. Any test.extend() and test.use() calls take priority over config options.
Required user changes: if someone used to define fixture options with test.extend(), overriding them in config will stop working. The solution is to add `{ option: true }`.
```
// Old code
export const test = base.extend<{ myOption: number, myFixture: number }>({
myOption: 123,
myFixture: ({ myOption }, use) => use(2 * myOption),
});
// New code
export const test = base.extend<{ myOption: number, myFixture: number }>({
myOption: [123, { option: true }],
myFixture: ({ myOption }, use) => use(2 * myOption),
});
```
- Each overload, e.g. for `page.evaluate`, shows a nice autocomplete doc,
not only the first one.
- We can have multiple overloads directly on the docs page, e.g.
`test.skip(title, fn)` and `test.skip(condition, description)`.
These overloads are internally named `Test.skip#1` and all aliased
to `test.skip`.
Each hook gets its own test scope. This is not too useful for
object fixtures like `page` (although one can use a page in
`beforeAll` to save storage state), but much more useful for option
fixtures like `viewport`.
