Add create function template and fix some minor template bugs (#23)

api/error.go

@@ -1,10 +1,11 @@
-// Code generated by go generate; DO NOT EDIT.
+// Code generated by "make api"; DO NOT EDIT.
 package api
 
 import (
 	"encoding/json"
 
 	"github.com/fatih/structs"
+
 	"github.com/hashicorp/watchtower/api/internal/strutil"
 )