Add FollowEmitter.stop() to typescript declaration file (#230)

diff --git a/lib/nano.d.ts b/lib/nano.d.ts
index b59a6fc..cf564fb 100644
--- a/lib/nano.d.ts
+++ b/lib/nano.d.ts
@@ -54,6 +54,7 @@
 
   interface FollowEmitter extends EventEmitter {
     follow(): void;
+    stop(): void;
   }
 
   interface UUIDObject {