Merge #9375

9375: feat: Highlight exit and yield points r=Veykril a=Veykril

![Code_YBHOCF3DbU](https://user-images.githubusercontent.com/3757771/123128986-e1270a80-d44b-11eb-9854-065459a2dd50.png)
![Code_YyMhqES0LX](https://user-images.githubusercontent.com/3757771/123128988-e1bfa100-d44b-11eb-9c81-6a6031aad740.png)

Fixes #4691
Fixes #9365

Co-authored-by: Lukas Wirth <[email protected]>

Author: bors[bot]

crates/hir/src/lib.rs

@@ -2075,10 +2075,15 @@ impl Type {
     pub fn is_unit(&self) -> bool {
         matches!(self.ty.kind(&Interner), TyKind::Tuple(0, ..))
     }
+
     pub fn is_bool(&self) -> bool {
         matches!(self.ty.kind(&Interner), TyKind::Scalar(Scalar::Bool))
     }
 
+    pub fn is_never(&self) -> bool {
+        matches!(self.ty.kind(&Interner), TyKind::Never)
+    }
+
     pub fn is_mutable_reference(&self) -> bool {
         matches!(self.ty.kind(&Interner), TyKind::Ref(hir_ty::Mutability::Mut, ..))
     }