[mlir][NFC] Tidy up the doc comment on CastInfo for Types

This had quite a few grammatical errors and typos.

Author: River707

mlir/include/mlir/IR/Types.h

@@ -334,16 +334,16 @@ struct CastInfo<
                      std::is_base_of_v<mlir::Type, From>>>
     : NullableValueCastFailed<To>,
       DefaultDoCastIfPossible<To, From, CastInfo<To, From>> {
-  /// Arguments are taken as mlir::Type here and not as From.
-  /// Because when casting from an intermediate type of the hierarchy to one of
-  /// its children, the val.getTypeID() inside T::classof will use the static
-  /// getTypeID of the parent instead of the non-static Type::getTypeID return
-  /// the dynamic ID. so T::classof would end up comparing the static TypeID of
-  /// The children to the static TypeID of its parent making it impossible to
-  /// downcast from the parent to the child
+  /// Arguments are taken as mlir::Type here and not as `From`, because when
+  /// casting from an intermediate type of the hierarchy to one of its children,
+  /// the val.getTypeID() inside T::classof will use the static getTypeID of the
+  /// parent instead of the non-static Type::getTypeID that returns the dynamic
+  /// ID. This means that T::classof would end up comparing the static TypeID of
+  /// the children to the static TypeID of its parent, making it impossible to
+  /// downcast from the parent to the child.
   static inline bool isPossible(mlir::Type ty) {
     /// Return a constant true instead of a dynamic true when casting to self or
-    /// up the hierarchy
+    /// up the hierarchy.
     return std::is_same_v<To, std::remove_const_t<From>> ||
            std::is_base_of_v<To, From> || To::classof(ty);
   }