Usually, we can just chain two locators with `>>` to implement
`Locator.locator(locator)`. However, this does not play nicely with more
advanced inner locators like `or` and `and`:
```ts
const child = page.locator('input').or(page.locator('button'));
page.locator('parent').locator(child);
```
One would expect the above to locate "input or button" inside a
"parent". However, currently it locates "input inside a parent" or
"button", because it's translated to `parent >> input >>
internal:or="button"`.
To fix this, we have to wrap inner locator into `internal:chain` and
query it separately from the parent.
Fixes#23724.
So, the following will work:
```
page.frameLocator('iframe').locator('span').or(page.frameLoactor('iframe').locator('div'))
```
The following will not work, because frame locators are not exactly the
same:
```
page.frameLocator('#iframe1').locator('span').or(page.frameLoactor('#iframe2').locator('div'))
```
Also improve the error message to be more readable and include the
locator.
Fixes#23697.
Chained selectors where the second part starts with a scope did not work
before:
```ts
page.locator('div').locator(':scope + span')
page.locator('div >> +span')
```
There is no locator counterpart for it. Instead, produce a regex.
Also fix locator generator to not produce incorrect locator in this
case.
Fixes#21649.
Following the `getByText()` and other methods:
- By default, matching is substring and case-insensitive. Before, it was
only case-insensitive, but not substring.
- With new option `exact: true`, matching is full string and
case-sensitive.
- Matching always normalizes whitespace.
- Codegen generates `exact: false` by default.
- `internal:role` treats `[name="foo"i]` as non-exact match.
Various fixes:
- Updated `getByRole` docs to match the reality.
- Locator generator edge cases.
- Rename internal selectors `has`, `control` and `attr` to
`internal:has`, `internal:control` and `internal:attr`.
- Fix `getByLabel()` to respect strictness, by introducing
`internal:label` selector.
- Move tests essential for ports to `selectors-by.spec`.
