Use ty, not w for the answer

Summary:
It doesn't matter much, but seeing `w` used here struck me as odd. I need
to tweak this code to change how loops work and I really didn't want to
extend the pattern of using `w` for a type.

Reviewed By: yangdanny97

Differential Revision: D85530071

fbshipit-source-id: 4877493dbe1b1e729ec5f2fb4aea052bf524bd81

Author: stroxler

pyrefly/lib/solver/solver.rs

@@ -343,8 +343,8 @@ impl Solver {
                 let lock = self.variables.lock();
                 if let Some(_guard) = lock.recurse(*x, recurser) {
                     let variable = lock.get(*x);
-                    if let Variable::Answer(w) = &*variable {
-                        *t = w.clone();
+                    if let Variable::Answer(ty) = &*variable {
+                        *t = ty.clone();
                         drop(variable);
                         drop(lock);
                         self.expand_with_limit(t, limit - 1, recurser);