TARGET_HELP: --target-help vs. --help=target

[Georg-Johann Lay]

Hi, I noticed a difference between --target-help and --help=target

Whilst --target-help also calls target hooh TARGET_HELP to display
additional information, using --help=target does not.

This is in sync with the documentation, but appears a bit odd. It this
a desired behaviour and is there a specific rationale to not display
all information with --help=target?

Thanks, Johann