fix(types): correct return type for Connection.prototype.transaction

Fix #9919
Re: mongodb/node-mongodb-native#3203

Author: vkarpov15

test/types/connection.test.ts

@@ -58,7 +58,7 @@ expectType<mongodb.Db>(conn.db);
 expectType<mongodb.MongoClient>(conn.getClient());
 expectType<Connection>(conn.setClient(new mongodb.MongoClient('mongodb://localhost:27017/test')));
 
-expectType<Promise<string>>(conn.transaction<string>(async(res) => {
+expectType<Promise<void>>(conn.transaction(async(res) => {
   expectType<mongodb.ClientSession>(res);
   return 'a';
 }));

types/connection.d.ts

@@ -197,7 +197,7 @@ declare module 'mongoose' {
        * async function executes successfully and attempt to retry if
        * there was a retryable error.
        */
-    transaction<U = any>(fn: (session: mongodb.ClientSession) => Promise<U>): Promise<U>;
+    transaction(fn: (session: mongodb.ClientSession) => Promise<any>): Promise<void>;
 
     /** Switches to a different database using the same connection pool. */
     useDb(name: string, options?: { useCache?: boolean, noListener?: boolean }): Connection;