docs: update address-ipfs-on-web.md

[lidel]

This PR removes some legacy examples which predate subdomain gateways and native protocol handler work in Brave, and updates related paragraphs.

Feel free to adjust phrasing if needed.

[ElPaisano]

Made some writing edits https://github.com/ipfs/ipfs-docs/pull/1682/commits/1aa242913fa31cd689d6cd7b608daf3562d31016 @lidel. Merging now