feat(core): export BuiltinServerFunctions type (#279)

Author: JianJroh

packages/core/src/index.ts

@@ -1,4 +1,5 @@
 export { createDevToolsContext } from './node/context'
 export type { DevToolsInternalContext, InternalAnonymousAuthStorage } from './node/context-internal'
 export { DevTools } from './node/plugins'
+export type { BuiltinServerFunctions } from './node/rpc'
 export { createDevToolsMiddleware } from './node/server'