Update Config comment in API Service interface

[prafgup]

What I did
Updated the outdated comment for Config method in Service interface for API package.

• Prev Comment - // Convert translate compose model into backend's native format
• Updated Comment - // Config executes the equivalent to a compose config
• Ref - https://docs.docker.com/engine/reference/commandline/compose_config/

• compose/cmd/compose/config.go

  Line 123 in 8318f66

  func runConfig(ctx context.Context, streams api.Streams, backend api.Service, opts configOptions, services []string) error {

Related issue

closes #10839

[prafgup]

Hey @milas, @glours can you help with a review here :)

[prafgup]

Tagging a few more maintainers to provide a review :) @nicksieger @ndeloof @StefanScherer @ulyssessouza @laurazard