Update term for use in more places

Replace use of `ty()` on term and use it in more places. This will allow more flexibility in the
future, but slightly worried it allows items which are consts which only accept types.

src/rustdoc-json-types/lib.rs

@@ -148,7 +148,7 @@ pub struct TypeBinding {
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 #[serde(rename_all = "snake_case")]
 pub enum TypeBindingKind {
-    Equality(Type),
+    Equality(Term),
     Constraint(Vec<GenericBound>),
 }
 
@@ -335,7 +335,7 @@ pub enum GenericParamDefKind {
 pub enum WherePredicate {
     BoundPredicate { ty: Type, bounds: Vec<GenericBound> },
     RegionPredicate { lifetime: String, bounds: Vec<GenericBound> },
-    EqPredicate { lhs: Type, rhs: Type },
+    EqPredicate { lhs: Type, rhs: Term },
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
@@ -359,6 +359,13 @@ pub enum TraitBoundModifier {
     MaybeConst,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
+pub enum Term {
+    Type(Type),
+    Constant(Constant),
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 #[serde(rename_all = "snake_case")]
 #[serde(tag = "kind", content = "inner")]