add comment and link to PR explaining why the refence type is there

Author: LiranCohen

packages/api/src/protocol.ts

@@ -1,3 +1,7 @@
+/**
+ * NOTE: Added reference types here to avoid a `pnpm` bug during build.
+ * https://github.com/TBD54566975/web5-js/pull/507
+ */
 /// <reference types="@tbd54566975/dwn-sdk-js" />
 
 import type { DwnMessage, DwnResponseStatus, Web5Agent } from '@web5/agent';

packages/api/src/record.ts

@@ -1,3 +1,7 @@
+/**
+ * NOTE: Added reference types here to avoid a `pnpm` bug during build.
+ * https://github.com/TBD54566975/web5-js/pull/507
+ */
 /// <reference types="@tbd54566975/dwn-sdk-js" />
 
 import type { Readable } from '@web5/common';