Fix formatting nits in Lattice.lean and Unit.lean

- Spa/Lattice.lean: add the missing space in the PointedLTSeries binder list
  ((f t : α) (n : ℕ)).
- Spa/Lattice/Unit.lean: use rfl instead of refl _, and split the ~200-column
  longestChain record literal across lines, one field per line.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lean/Spa/Lattice/Unit.lean

@@ -12,7 +12,11 @@ instance : FiniteHeightLattice PUnit where
   bot := PUnit.unit
   top := PUnit.unit
   height := 0
-  longestChain := { series := RelSeries.singleton _ PUnit.unit, head_series := refl _, last_series := refl _, length_series := refl _ }
+  longestChain :=
+    { series := RelSeries.singleton _ PUnit.unit
+      head_series := rfl
+      last_series := rfl
+      length_series := rfl }
   chains_bounded := boundedChains_of_subsingleton PUnit 0
 
 end Spa