the error message is not accurate

[qqqdan]

Feature Request

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

tiup uninstall grafana v5.4.0 Use tiup uninstall grafana --all if you want to remove all versions. Use tiup uninstall v5.4.0 --all if you want to remove all versions.

Describe the feature you'd like:

Use tiup uninstall grafana --all if you want to remove all versions. Use tiup uninstall grafana:v5.4.0 if you want to remove v5.4.0.

Why the featue is needed:

I can not know the correct command from the current message

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy: