fix: preserve js docs when directly passing options to betterAuth

Author: Bekacru

packages/better-auth/src/auth.ts

@@ -6,18 +6,19 @@ import type {
 	InferPluginTypes,
 	InferSession,
 	InferUser,
-	PreserveJSDoc,
 	PrettifyDeep,
 } from "./types";
 import { getBaseURL } from "./utils/url";
 import type { FilterActions, InferAPI } from "./types/api";
 import { BASE_ERROR_CODES } from "./error/codes";
 
+export type WithJsDoc<T, D> = Expand<T & D>;
+
 export const betterAuth = <O extends BetterAuthOptions>(
-	options: PreserveJSDoc<O>,
+	options: WithJsDoc<O, BetterAuthOptions>,
 ) => {
-	const authContext = init(options);
-	const { api } = getEndpoints(authContext, options);
+	const authContext = init(options as O);
+	const { api } = getEndpoints(authContext, options as O);
 	const errorCodes = options.plugins?.reduce((acc, plugin) => {
 		if (plugin.$ERROR_CODES) {
 			return {