feat(lattices): Make Pair<> members public (#1233)

Summary of types examined:

- `Min<T>`: T is not a lattice
- `set_union<T>`: is not a lattice
- map_union - not safe to expose map
- union_find<K> - K is not a lattice
- VecUnion<Lat> - not safe to expose vec
- WithTop<Lat>/WithBot<Lat> - already pub
- Pair<LatA, LatB> - Changed in this commit
- DomPair<LatKey, LatVal> - Already correctly done with left pub and
right private.
- Conflict<T> / Point<T> - T is not a lattice type.
- () - No nested types here.

lattices/src/pair.rs

@@ -10,8 +10,11 @@ use crate::{DeepReveal, IsBot, IsTop, LatticeBimorphism, LatticeFrom, LatticeOrd
 #[derive(Copy, Clone, Debug, Default, Eq)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Pair<LatA, LatB> {
-    a: LatA,
-    b: LatB,
+    /// The "left" Lattice of the Pair lattice.
+    pub a: LatA,
+
+    /// The "right" Lattice of the Pair lattice.
+    pub b: LatB,
 }
 
 impl<LatA, LatB> Pair<LatA, LatB> {