docs: add entry argument to serve command (vuejs#1724)

timwis · Akryum · commit 226291c1e9ae · 2018-07-04T13:19:12.000+02:00
This argument is present in the help text but not in the docs.
diff --git a/docs/guide/cli-service.md b/docs/guide/cli-service.md
@@ -32,7 +32,7 @@ npx vue-cli-service serve
 ## vue-cli-service serve
 
 ```
-Usage: vue-cli-service serve [options]
+Usage: vue-cli-service serve [options] [entry]
 
 Options:
 
