Description of problem:
'dnf repoquery --help' shows general dnf help, but not the repoquery help as one would expect.

Version-Release number of selected component (if applicable):
dnf-plugins-core-0.1.21-2.fc23.noarch

How reproducible:
Always

Steps to Reproduce:
1. dnf repoquery --help

Actual results:
usage: dnf [options] COMMAND

List of Main Commands

autoremove                remove all unneeded packages that were originally installed as dependencies
check-update              check for available package upgrades
clean                     remove cached data
distro-sync               synchronize installed packages to the latest available versions
downgrade                 downgrade a package
group                     display, or use, the groups information
help                      display a helpful usage message
history                   display, or use, the transaction history
info                      display details about a package or group of packages
install                   install a package or packages on your system
list                      list a package or groups of packages
makecache                 generate the metadata cache
mark                      mark or unmark installed packages as installed by user.
provides                  find what package provides the given value
reinstall                 reinstall a package
remove                    remove a package or packages from your system
repolist                  display the configured software repositories
repository-packages       run commands on top of all packages in given repository
search                    search package details for the given string
updateinfo                display advisories about packages
upgrade                   upgrade a package or packages on your system
upgrade-to                upgrade a package on your system to the specified version

List of Plugin Commands

builddep                  Install build dependencies for package or spec file
config-manager            manage dnf configuration options and repositories
copr                      Interact with Copr repositories.
debuginfo-install         install debuginfo packages
download                  Download package to current directory
langavailable             Search available langpack packages
langinfo                  Show langpack packages for a given language
langinstall               Install the given packages
langlist                  Show installed languages
langremove                Remove the given packages
needs-restarting          determine updated binaries that need restarting
playground                Interact with Playground repository.
repoquery                 search for packages matching keyword
reposync                  download all packages from remote repo

optional arguments:
  --allowerasing        allow erasing of installed packages to resolve
                        dependencies
  -b, --best            try the best available package versions in
                        transactions.
  -C, --cacheonly       run entirely from system cache, don't update cache
  -c [config file], --config [config file]
                        config file location
  -d [debug level], --debuglevel [debug level]
                        debugging output level
  --debugsolver         dumps detailed solving results into files
  --showduplicates      show duplicates, in repos, in list/search commands
  -e ERRORLEVEL, --errorlevel ERRORLEVEL
                        error output level
  --rpmverbosity [debug level name]
                        debugging output level for rpm
  -q, --quiet           quiet operation
  -v, --verbose         verbose operation
  -y, --assumeyes       Automatically answer yes for all questions
  --assumeno            Automatically answer no for all questions
  --version             show DNF version and exit
  --installroot [path]  set install root
  --enablerepo [repo]
  --disablerepo [repo]
  -x [package], --exclude [package]
                        exclude packages by name or glob
  --disableexcludes [repo]
                        disable excludes
  --repofrompath [repo,path]
                        label and path to additional repository, can be
                        specified multiple times.
  --noplugins           disable all plugins
  --nogpgcheck          disable gpg signature checking
  --disableplugin [plugin]
                        disable plugins by name
  --color COLOR         control whether color is used
  --releasever RELEASEVER
                        override the value of $releasever in config and repo
                        files
  --setopt SETOPTS      set arbitrary config and repo options
  --refresh             set metadata as expired before running the command
  -4                    resolve to IPv4 addresses only
  -6                    resolve to IPv6 addresses only
  --downloadonly        only download packages
  -h, --help            show help


Expected results:
repoquery help, i.e. description of '--whatprovides' and others.

Additional info:
It's not straightforward that the manual page for repoquery is 'dnf.plugin.repoquery', and 'man repoquery' shows manual page for yum repoquery, so users very probably intuitively run: 'dnf repoquery --help' to get the insight into the command, but they learn nothing about the supported arguments. It's probably the same with other plugins as well.