doc: minor formatting and consistency fixes

This patch includes some minor consistency fixes I noticed when reading
the man page:
- A few commands had extra blank lines before starting their description
  which was causing extra whitespace to be added to the description.
- Some information relevant to commands was nested under example
  commands because of leading whitespace (mostly the information about
  `-nevra` commands).
- Some example commands followed their description, while most other
  examples have the command first and then the description. This changes
  all examples to the latter for consistency.
- Renamed the `Examples` header to `Repoquery Examples` similar to other
  example headers
- Fixed typo in repoquery examples (ligttpd -> lighttpd)
- Added parameter names to `swap` description

Also this updates the man page file name in the README (dnf.8 -> dnf4.8)

README.rst

@@ -57,7 +57,7 @@ If you want to build the manpages, use the option ``-DWITH_MAN=0`` with cmake.
 
 Man pages will be located in ``build/doc`` and can be read with ``man -l``, e.g::
 
-    man -l build/doc/dnf.8
+    man -l build/doc/dnf4.8
 
 =============================
  Building and installing rpm

doc/command_ref.rst

@@ -165,7 +165,6 @@ Options
 .. _disableexcludes-label:
 
 ``--disableexcludes=[all|main|<repoid>], --disableexcludepkgs=[all|main|<repoid>]``
-
     Disable the configuration file excludes. Takes one of the following three options:
 
     * ``all``, disables all configuration file excludes
@@ -541,7 +540,6 @@ Check-Update Command
 
 
 ``dnf [options] check-update [--changelogs] [<package-file-spec>...]``
-
     Non-interactively checks if updates of the specified packages are available. If no ``<package-file-spec>`` is given, checks whether any updates at all are available for your system. DNF exit code will be 100 when there are updates available and a list of the updates will be printed, 0 if not and 1 if an error occurs. If ``--changelogs`` option is specified, also changelog delta of packages about to be updated is printed.
 
     Please note that having a specific newer version available for an installed package (and reported by ``check-update``) does not imply that subsequent ``dnf upgrade`` will install it. The difference is that ``dnf upgrade`` has restrictions (like package dependencies being satisfied) to take into account.
@@ -1205,9 +1203,9 @@ Remove Examples
     Remove packages not present in any repository, but don't remove the ``tito``
     and ``acpi`` packages (they still might be removed if they depend on some of the removed packages).
 
-Remove older versions of duplicated packages (an equivalent of yum's `package-cleanup --cleandups`)::
+``dnf remove --duplicates``
+    Remove older versions of duplicated packages (an equivalent of yum's `package-cleanup --cleandups`).
 
-    dnf remove --duplicates
 
 .. _repoinfo_command-label:
 
@@ -1476,52 +1474,41 @@ are displayed in the standard NEVRA notation.
     resolve capabilities to originating package(s).
 
 
-Examples
---------
+Repoquery Examples
+------------------
 
-Display NEVRAs of all available packages matching ``light*``::
+``dnf repoquery 'light*'``
+    Display NEVRAs of all available packages matching ``light*``
 
-    dnf repoquery 'light*'
+``dnf repoquery-na 'light*.noarch'``
+    Display NEVRAs of all available packages matching name ``light*`` and architecture ``noarch`` (accepts only arguments in the "<name>.<arch>" format)
 
-Display NEVRAs of all available packages matching name ``light*`` and architecture ``noarch`` (accepts only arguments in the "<name>.<arch>" format)::
+``dnf repoquery --requires lighttpd``
+    Display requires of all lighttpd packages
 
-    dnf repoquery-na 'light*.noarch'
+``dnf repoquery --requires python --resolve``
+    Display packages providing the requires of python packages
 
-Display requires of all lighttpd packages::
+``dnf repoquery --source lighttpd``
+    Display source rpm of lighttpd package
 
-    dnf repoquery --requires lighttpd
+``dnf repoquery --file /etc/lighttpd/lighttpd.conf``
+    Display package name that owns the given file
 
-Display packages providing the requires of python packages::
+``dnf repoquery --queryformat '%{name}.%{arch} : %{reponame}' lighttpd``
+    Display name, architecture and the containing repository of all lighttpd packages
 
-    dnf repoquery --requires python --resolve
+``dnf repoquery --whatprovides webserver``
+    Display all available packages providing "webserver"
 
-Display source rpm of ligttpd package::
+``dnf repoquery --whatprovides webserver --arch i686``
+    Display all available packages providing "webserver" but only for "i686" architecture
 
-    dnf repoquery --source lighttpd
+``dnf repoquery --duplicates``
+    Display duplicate packages
 
-Display package name that owns the given file::
-
-    dnf repoquery --file /etc/lighttpd/lighttpd.conf
-
-Display name, architecture and the containing repository of all lighttpd packages::
-
-    dnf repoquery --queryformat '%{name}.%{arch} : %{reponame}' lighttpd
-
-Display all available packages providing "webserver"::
-
-    dnf repoquery --whatprovides webserver
-
-Display all available packages providing "webserver" but only for "i686" architecture::
-
-    dnf repoquery --whatprovides webserver --arch i686
-
-Display duplicate packages::
-
-    dnf repoquery --duplicates
-
-Display source packages that require a <provide> for a build::
-
-    dnf repoquery --disablerepo="*" --enablerepo="*-source" --arch=src --whatrequires <provide>
+``dnf repoquery --disablerepo="*" --enablerepo="*-source" --arch=src --whatrequires <provide>``
+    Display source packages that require a <provide> for a build
 
 .. _repository_packages_command-label:
 
@@ -1669,7 +1656,7 @@ Swap Command
 
 ``dnf [options] swap <remove-spec> <install-spec>``
 
-    Remove spec and install spec in one transaction. Each ``<spec>`` can be either a
+    Remove ``remove-spec`` and install ``install-spec`` in one transaction. Each ``<spec>`` can be either a
     :ref:`<package-spec> <specifying_packages-label>`, which specifies a package directly, or a
     ``@<group-spec>``, which specifies an (environment) group which contains it. Automatic
     conflict solving is provided in DNF by the --allowerasing option that provides the functionality of the swap