doc: man: Add some details to subcommands

The subcommands descriptions for create, release-from and flashscript
had some extra details not available in the argparse/cli help. Migrate
these descriptions from the old to the new manpage by overwriting the
subcommand descriptions.

Signed-off-by: Jonas Rebmann <jre@pengutronix.de>

Author: jonrebm

doc/man/client.rst

@@ -31,6 +31,20 @@ Options
    available subcommands : @skip
         skip.
 
+   create : @replace
+        add a new place with the name specified via ``--place`` or the
+        ``LG_PLACE`` environment variable.
+
+   release-from : @replace
+        Atomically release a place, but only if acquired by a specific user.
+
+        Note that this command returns success as long as the specified user no
+        longer owns the place, meaning it may be acquired by another user or
+        not at all.
+
+   flashscript : @replace
+        Run arbitrary script with arguments to flash device
+
 
 Configuration File
 ------------------