docs: use locator-first examples in the API reference

[luantaraschi]

Closes #46.

I checked every candidate against Playwright's own doc source (microsoft/playwright, docs/src/api/*.md) rather than going from memory, since the issue asks to replace only where current guidance clearly prefers something better. Three groups came out of it.

Deprecated, replaced. locator.type carries a deprecation note verbatim:

* deprecated: In most cases, you should use [method: Locator.fill] instead. You only need to press keys one by one if there is special keyboard handling on the page - in this case use [method: Locator.pressSequentially].

The "clear and type" example now shows fill for the ordinary case and pressSequentially for the per-key one, labelled so a reader knows which situation each is for, rather than silently swapping one for the other.

Discouraged, replaced. Six page-level selector APIs in the reference carry a discouraged marker pointing at their locator equivalent:

API	note in class-page.md
page.click	Use locator-based Locator.click instead
page.fill	Use locator-based Locator.fill instead
page.selectOption	Use locator-based Locator.selectOption instead
page.setInputFiles	Use locator-based Locator.setInputFiles instead
page.hover	Use locator-based Locator.hover instead
page.dblclick	Use locator-based Locator.dblclick instead

Those cover the form, mouse, network-wait, data-driven, popup and download examples. Where the element was described by role in prose I used getByRole rather than mechanically wrapping the CSS selector in page.locator(...), since the reference already teaches role-first locators a few sections earlier; where the example was pinned to a specific id or class I kept that selector and just moved it into a locator.

Not touched, on purpose. page.keyboard.type stays. It has no deprecation or discouraged note, and class-keyboard.md still calls it "the high level api" and uses it in its own example. Replacing it would have been the audit overreaching. I also found no waitForTimeout and no networkidle anywhere in the file, so nothing to do on the two patterns the issue names first.

What I ran, on Windows with Node 22.20.0:

• npm test in skills/playwright-skill: 12 pass, 0 fail
• npx skills-ref@0.1.5 validate . in the same directory, which is what CI runs: Valid skill: .
• a grep afterwards for the whole discouraged set to confirm none survived in the file

Docs-only change, 22 lines added and 19 removed, no behaviour anywhere.