inets: Document sending status with mod_esi

[jchristgit]

I think this was previously undocumented because of its roots in CGI (https://stackoverflow.com/questions/25800385/how-to-send-response-headers-and-status-from-cgi-scripts), but I figured it would be nice to explicitly mention it in the docs regardless.
A test for this is already done as part of httpd_SUITE:esi, line 949:

    ok = http_status("GET /cgi-bin/erl/httpd_example:new_status_and_location ",
                     Config, [{statuscode, 201},
                              {header, "location"}]).

which calls src/http_server/httpd_example.erl, doing:

new_status_and_location(SessionID, Env, Input) ->
    mod_esi:deliver(SessionID, new_status_and_location(Env, Input)).

new_status_and_location(_Env,_Input) ->
  "status:201 Created\r\n Location: http://www.yahoo.com\r\n\r\n".

[github-actions]

CT Test Results

    2 files    21 suites   14m 6s ⏱️
336 tests 331 ✔️ 5 💤 0 ❌
561 runs  553 ✔️ 8 💤 0 ❌

Results for commit ec373d4.

♻️ This comment has been updated with latest results.

To speed up review, make sure that you have read Contributing to Erlang/OTP and that all checks pass.

See the TESTING and DEVELOPMENT HowTo guides for details about how to run test locally.

Artifacts

• Complete CT logs (Download Logs)
• HTML Documentation (Download HTML Docs)
• Windows Installer

// Erlang/OTP Github Action Bot

[IngelaAndin]

At first glance this looks good. Even if we are thinking about maybe removing ordinary CGI support (not decided) ESI support will still be part of what we want to keep. Things will however slow down a little due to summer vacation period, so merge decision may take longer than usual, please have patience.