Refactor UsageInfo and SubstitutionMap

This commit refactors the `UsageInfo` struct to use a single
`HashSet<Address>` for both used and assigned addresses, simplifying the
logic. It also updates the `SubstitutionMap` to use a similar approach
for tracking assigned values.

Key changes include:
- `UsageInfo` now has `used` and `assigned` fields of type
  `HashSet<Address>`.
- `SubstitutionMap`'s `add_local`, `add_global`, `add_upvalue`,
  `remove_local`, `remove_global`, and `remove_upvalue` methods have
  been replaced with a generic `add_value` and `remove_value` that
  operate on `Address`.
- The `Optimizer`'s `collect_pattern_usage` and `visit_node` methods
  have been updated to use the new `UsageInfo` and `SubstitutionMap`
  APIs.
- `Get` and `Set` nodes now use `sub.map_address` to transform addresses
  based on the current substitution.

src/ast/compiler/bound_nodes.rs

@@ -237,7 +237,9 @@ impl<T> BoundKind<T> {
             BoundKind::Constant(v) => format!("CONST({})", v),
             BoundKind::Get { addr, name } => format!("GET({}, {:?})", name.name, addr),
             BoundKind::Set { addr, .. } => format!("SET({:?})", addr),
-            BoundKind::Define { name, addr, kind, .. } => {
+            BoundKind::Define {
+                name, addr, kind, ..
+            } => {
                 let k_str = match kind {
                     DeclarationKind::Variable => "VAR",
                     DeclarationKind::Parameter => "PARAM",