Improve specificity of iterator typing

Author: sck451

src/Option/None.ts

@@ -138,7 +138,7 @@ export class None<T = never> {
    * Return an iterator over the {@link Some} value.
    * @returns A JavaScript iterator over 0 or 1 elements.
    */
-  *[Symbol.iterator](): Iterator<T> {}
+  *[Symbol.iterator](): IteratorObject<T, void, never> {}
 
   /**
    * Return `optionB` if {@link Some}, otherwise `None`.

src/Option/Some.ts

@@ -147,7 +147,7 @@ export class Some<T> {
    * Return an iterator over the {@link Some} value.
    * @returns A JavaScript iterator over 0 or 1 elements.
    */
-  *[Symbol.iterator](): Iterator<T> {
+  *[Symbol.iterator](): IteratorObject<T, void, never> {
     yield this.value;
   }
 

src/Result/Err.ts

@@ -145,7 +145,7 @@ export class Err<T = never, E = unknown> {
    * Get an iterator over the `Ok` value.
    * @returns An iterator yielding the `Ok` value or nothing if `Err`.
    */
-  *[Symbol.iterator](): Iterator<T> {}
+  *[Symbol.iterator](): IteratorObject<T, void, never> {}
 
   /**
    * Unwrap the `Ok` value, or throw an error if `Err`.

src/Result/Ok.ts

@@ -144,7 +144,7 @@ export class Ok<T, E = never> {
    * Get an iterator over the `Ok` value.
    * @returns An iterator yielding the `Ok` value or nothing if `Err`.
    */
-  *[Symbol.iterator](): Iterator<T> {
+  *[Symbol.iterator](): IteratorObject<T, void, never> {
     yield this.value;
   }