Apply suggestions from code review

Co-authored-by: Myk <myk.taylor@gmail.com>

Author: chdoc

docs/dev/Lua API.rst

@@ -1703,7 +1703,7 @@ Units module
   ``dfhack.units.isOwnCiv`` or another appropriate predicate on the unit
   in question.
 
-* ``dfhack.units.setGoal(unit, pos, goal)``
+* ``dfhack.units.setPathGoal(unit, pos, goal)``
 
   Set target coordinates and goal (of type ``df.unit_path_goal``) for the given
   unit. In case of a change, also clears the unit's current path.

library/modules/Units.cpp

@@ -946,8 +946,7 @@ void Units::setPathGoal(df::unit *unit, df::coord pos, df::unit_path_goal goal)
 
     if (unit->flags1.bits.rider && unit->mount_type == df::rider_positions_type::STANDARD)
     {
-        auto mount = df::unit::find(unit->relationship_ids[df::unit_relationship_type::RiderMount]);
-        if (mount)
+        if (auto mount = df::unit::find(unit->relationship_ids[df::unit_relationship_type::RiderMount]))
         {
             mount->path.dest = pos;
             mount->path.goal = goal;