Rename EntrySets as EntryStates.

"Set" doesn't make much sense here, we refer to domain values as "state"
everywhere else. (This name confused me for a while.)

compiler/rustc_mir_dataflow/src/lib.rs

@@ -18,7 +18,7 @@ pub use self::drop_flag_effects::{
     move_path_children_matching, on_all_children_bits, on_lookup_result_bits,
 };
 pub use self::framework::{
-    Analysis, Backward, Direction, EntrySets, Forward, GenKill, JoinSemiLattice, MaybeReachable,
+    Analysis, Backward, Direction, EntryStates, Forward, GenKill, JoinSemiLattice, MaybeReachable,
     Results, ResultsCursor, ResultsVisitor, SwitchIntEdgeEffects, fmt, graphviz, lattice,
     visit_results,
 };