Is your feature request related to a problem? Please describe.

There are some situations where a yaml tag is required. (encoding/yaml).Marshal does not support encoding tags and makes this impossible.

It looks like the authors of the original encoder were aware this may be desirable.

Describe the solution you'd like

Support encoding tags with an attribute.

import "encoding/yaml"

yaml.Marshal({
    some_key: "some value" @yaml.Tag("some tag")
})

Describe alternatives you've considered
Not sure.

Additional context

Maybe:

• @tag --inject equivalent in yaml used by kpt tool is a magic comment #Ref #422
• cmd/cue: tags across packages #1070