justice: implement code review suggestions

Author: master-spike

docs/justice.rst

@@ -2,23 +2,24 @@ justice
 =======
 
 .. dfhack-tool::
-    :summary: Commands related to the justice system
+    :summary: Commands related to the justice system.
     :tags: fort armok units
 
 This tool allows control over aspects of the justice system, such as the
 ability to pardon criminals.
 
-usage
+Usage
 -----
 
 ::
     justice pardon [--unit <id>]
 
-Pardon the selected unit or the one specified by unit id if provided. Currently
-only applies to prison time and doesn't cancel beatings or hammerings.
+Pardon the selected unit or the one specified by unit id (if provided).
+Currently only applies to prison time and doesn't cancel beatings or
+hammerings.
 
 
-options
+Options
 -------
 
 ``-u``, ``--unit <id>``

justice.lua

@@ -35,6 +35,8 @@ local command = positionals[1]
 
 if command == "pardon" then
     command_pardon(unit_id)
+elseif not command then
+    qerror('Missing command')
+else
+    qerror(("Unrecognised command: %s"):format(command))
 end
-
-qerror(("Unrecognised command: %s"):format(command))