curl: help category cleanups

- add 'mqtt' as a category
- add more protocol categories to several options
- make --data worded better to also cover MQTT

Closes #22447

tests/data/data1461.txt

@@ -1,5 +1,5 @@
 Usage: curl [options...] <url>
- -d, --data <data>            HTTP POST data
+ -d, --data <data>            Post data
  -f, --fail                   Fail fast with no output on HTTP errors
  -I, --head                   Show document info only
  -H, --header <header/@file>  Pass custom header(s) to server
@@ -17,7 +17,7 @@ Usage: curl [options...] <url>
 This is not the full help; this menu is split into categories.
 Use "--help category" to get an overview of all categories, which are:
 auth, connection, curl, deprecated, dns, file, ftp, global, http, imap, ldap,%SP
-output, pop3, post, proxy, scp, sftp, smtp, ssh, telnet, tftp, timeout, tls,%SP
-upload, verbose.
+mqtt, output, pop3, post, proxy, scp, sftp, smtp, ssh, telnet, tftp, timeout,%SP
+tls, upload, verbose.
 Use "--help all" to list all options
 Use "--help [option]" to view documentation for a given option

tests/data/test1462

@@ -39,6 +39,7 @@ Unknown category provided, here is a list of all categories:
  http        HTTP and HTTPS protocol
  imap        IMAP protocol
  ldap        LDAP protocol
+ mqtt        MQTT protocol
  output      File system output
  pop3        POP3 protocol
  post        HTTP POST specific