Slight wording error when port forward already exists

[GCrispino]

Is your feature request related to a problem? Please describe.
This would be a small wording change request. When we try to open a port-forward on a pod that already has one, the following message is printed:

A PortForward already exist for pod *podname*

Describe the solution you'd like
I believe the correct phrasing would be

A PortForward already *exists* for pod *podname*

Describe alternatives you've considered
N/A

Additional context
There are two occurrences of this wording on the codebase:

1. https://github.com/derailed/k9s/blob/master/internal/view/pf_extender.go#L60
2. https://github.com/derailed/k9s/blob/master/internal/view/container.go#L177

I could fix them if the maintainers agree this should be changed.

Cheers!

[derailed]

@GCrispino Thank you! Fixed v0.25.19