Support multiple ResultTags annotations

[jmmills]

As multiple  As annotations are supported, it would make sense to support multiple ResultTag annotations.

Currently this code fails with cannot apply more than one line of ResultTags

func main() {
	app := fx.New(
		fx.Provide(
			fx.Annotate(
				func() *bytes.Buffer {
					return bytes.NewBuffer([]byte("Hello!"))
				},
				fx.ResultTags(`name:"a"`),
				fx.ResultTags(`name:"b"`),
			),
		),
		fx.Invoke(
			fx.Annotate(
				func(a, b *bytes.Buffer) {
					fmt.Println(a.String())
					fmt.Println(b.String())
				},
				fx.ParamTags(
					`name:"a"`,
					`name:"b"`,
				),
			),
		),
	)
	app.Run()
}

A work-around is possible by providing multiple copies of the same instance of a type, however it is less intuitive.

fx.Provide(
    fx.Annotate(
        func() (*bytes.Buffer, *bytes.Buffer) {
            a := bytes.NewBuffer([]byte("Hello!"))
            b := a
            return a, b
        },
        fx.ResultTags(`name:"a"`, `name:"b"`),
    ),
)

Is this a breaking change?
It should not be a breaking change as nothing (sans tests) should rely on app failure for multiple result tag annotations.