test: add type test

Author: andymina

src/change_stream.ts

@@ -751,7 +751,7 @@ export class ChangeStream<
     } finally {
       try {
         await this.close();
-      } catch (error) {
+      } catch {
         // We're not concerned with errors from close()
       }
     }

test/types/change_stream.test-d.ts

@@ -214,3 +214,7 @@ expectError(collection.watch<number, number>());
 collection
   .watch<{ a: number }, { b: boolean }>()
   .on('change', change => expectType<{ b: boolean }>(change));
+
+expectType<AsyncGenerator<ChangeStreamDocument, void, void>>(
+  collection.watch()[Symbol.asyncIterator]()
+);