A faster function to replace node by path

[idleGG]

Describe the solution you'd like

Add a new function to replace node field based on the old one, and use only one search by path.

The function may be like:

// File: `thrift/generic/node.go`
func (self *Node) ReplaceByPath(f func(Node) Node, path ...Path) (exist bool, err error) {
	if len(path) == 0 {
		*self = f(*self)
		return true, nil
	}
	if err := self.Check(); err != nil {
		return false, err
	}
	// search source node by path
	var v = self.GetByPath(path...)
	if v.IsError() {
		return false, v
	} else {
		exist = true
	}
	sub := f(v)
	if sub.IsError() {
		return true, sub
	}
	err = self.replace(v, sub)
	return
}

[AsterDY]

welcome PR