docs: Use locator.first() in locator.or examples

[EvanCahill]

The examples used for Locator.or and 'Matching one of the two alternative locators' are inconsistent. The latter includes .first() while the former doesn't.

This PR adds the same language used in 'Matching one of the two alternative locators' to the method documentation and updates the example to match.

[github-actions]

Test results for "tests 1"

8 flaky

⚠️ [firefox-page] › page/page-evaluate.spec.ts:403:3 › should throw for too deep reference chain @firefox-ubuntu-22.04-node18
⚠️ [chromium-library] › library/popup.spec.ts:264:3 › should not throw when click closes popup @ubuntu-20.04-chromium-tip-of-tree
⚠️ [webkit-library] › library/browsercontext-clearcookies.spec.ts:146:3 › should remove cookies by name and domain @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › library/browsercontext-proxy.spec.ts:27:3 › should work when passing the proxy only on the context level @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › library/inspector/cli-codegen-1.spec.ts:147:7 › cli codegen › should make a positioned click on a canvas @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › library/proxy.spec.ts:93:11 › should proxy local network requests › with other bypasses › link-local @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › library/selector-generator.spec.ts:328:7 › selector generator › should prioritize attributes correctly › type @webkit-ubuntu-22.04-node18
⚠️ [webkit-page] › page/page-set-input-files.spec.ts:147:3 › should upload large file @webkit-ubuntu-22.04-node18

37395 passed, 650 skipped
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Merge workflow run.