Cleanup context.go

flag_string.go

@@ -76,7 +76,7 @@ func (f *StringFlag) Apply(set *flag.FlagSet) error {
 // String looks up the value of a local StringFlag, returns
 // "" if not found
 func (c *Context) String(name string) string {
-	if fs := lookupFlagSet(name, c); fs != nil {
+	if fs := c.lookupFlagSet(name); fs != nil {
 		return lookupString(name, fs)
 	}
 	return ""