docs: add send options and methods changes to Express 5 migration guide

[22BRS1317]

Description

Fixes #1868

Added missing documentation to the Express 5 migration guide for
breaking changes from the send package that directly affect
Express users upgrading from v4 to v5.

Changes made

en/guide/migrating-5.md

• Added new section res.sendFile() and express.static() options
  documenting removed options:

  • hidden → use dotfiles instead
  • from → use root instead

• Added new section Removed send methods documenting methods
  no longer exported by the send package:

  • send.etag() → use etag option instead
  • send.index() → use index option instead
  • send.maxage() → use maxAge option instead
  • send.root() → use root option instead

• Updated table of contents with links to both new sections

Motivation

Developers upgrading from Express 4 to Express 5 who relied on
these options and methods would encounter silent breakage with
no guidance in the migration guide. This PR fills that gap.

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[krzysdz]

I haven't reviewed it thoroughly yet, but I'm pretty sure that some of the changes to send that you've listed do not directly affect Express users.

[22BRS1317]

I haven't reviewed it thoroughly yet, but I'm pretty sure that some of the changes to send that you've listed do not directly affect Express users.

Thank you for the feedback! You're right — after reviewing
this more carefully, I can see that send.etag(), send.root(),
send.index(), and send.maxage() were internal methods of the
send package used by Express internally, not methods that
Express users called directly in their applications.

I'll update the PR to remove that section and keep only the
changes that are directly relevant to Express users (the
res.sendFile() and express.static() options changes).

Sorry for the noise and thanks for the review!