Update revalidateTag examples to use the new two-argument signature (#92065)
### What?
Updated all documentation examples of `revalidateTag` to use the new
two-argument signature (`revalidateTag(tag, 'max')`) instead of the
deprecated single-argument form (`revalidateTag(tag)`).
### Why?
The `revalidateTag` API now requires a second `profile` argument. Using
the old single-argument form causes a TypeScript build error: "Expected
2 arguments, but got 1". Several documentation pages still showed the
old signature, which would lead developers to write code that fails to
compile.
### How?
Updated 14 call sites across 6 documentation files to pass `'max'` as
the second argument, which is the recommended default for
stale-while-revalidate semantics:
- `docs/01-app/02-guides/incremental-static-regeneration.mdx`
- `docs/01-app/02-guides/redirecting.mdx`
- `docs/01-app/02-guides/caching-without-cache-components.mdx`
- `docs/01-app/02-guides/backend-for-frontend.mdx`
- `docs/01-app/02-guides/how-revalidation-works.mdx`
- `docs/01-app/03-api-reference/04-functions/cacheTag.mdx`
The `revalidateTag.mdx` API reference page and `09-revalidating.mdx`
getting started page were already updated. The `self-hosting.mdx` cache
handler method signature (`async revalidateTag(tags)`) is unrelated and
left unchanged.