Deprecate aliased commands - #2214

@bjhargrave for each aliased command though we have had a warning that these would be removed in 0.19. I feel like enough warning has been given that warrants deletion of the code we no longer want to maintain. Open to what others think on this though!

we have had a warning that these would be removed in 0.19

I think my suggestion conforms with removing them since they no longer do anything useful and just emit a message with the proper command to use. My suggested is just a baby step to removing them by nudging the users to the proper command.

I still see many people using the old command forms since they are not forced to use the new forms. (I am not even sure they read the message :-) Just removing them without a nudge to the new command is harsher than it needs to be.

I think a smoother approach would be to continue to recognize the aliases but just exit after telling the user the replacement command (instead of executing the replacement command). This can help retrain users by telling them the new command.
Then in a later release, we can just remove all handling of the old aliases.

@bjhargrave We basically have been doing this except we don't exit - just warn. The issue called for removing all handling of the old aliases, but I thought adding the transitional class with the new deprecation warning was a good compromise.

continue to recognize the aliases but just exit after telling the user the replacement command

@bjhargrave I could do this though! I'll see what others think as well

Example output running ilab and then trying to run a removed command:

(venv) alina@fedora:~/dev/instruct-lab/cli/instructlab$ ilab
Usage: ilab [OPTIONS] COMMAND [ARGS]...

  CLI for interacting with InstructLab.

  If this is your first time running ilab, it's best to start with `ilab
  config init` to create the environment.

Options:
  --config PATH  Path to a configuration file.  [default:
                 /home/alina/.config/instructlab/config.yaml]
  -v, --verbose  Enable debug logging (repeat for even more verbosity)
  --version      Show the version and exit.
  --help         Show this message and exit.

Commands:
  config    Command Group for Interacting with the Config of InstructLab.
  data      Command Group for Interacting with the Data generated by...
  model     Command Group for Interacting with the Models in InstructLab.
  system    Command group for all system-related command calls
  taxonomy  Command Group for Interacting with the Taxonomy of InstructLab.

Aliases:
  chat      model chat
  generate  data generate
  serve     model serve
  train     model train
(venv) alina@fedora:~/dev/instruct-lab/cli/instructlab$ ilab evaluate
Command 'evaluate' not found. If this was an aliased command, please note that aliases have been deprecated in 0.19.0.
Please refer to the updated documentation for the new command structure.
Usage: ilab [OPTIONS] COMMAND [ARGS]...
Try 'ilab --help' for help.

Error: No such command 'evaluate'.

Aliases:
chat model chat
generate data generate
serve model serve
train model train

I think the help output should not mention the aliases. But if the user uses an old alias, the error message should state the replacement command to nudge the user.

One last thing, could you please update the CHANGELOG to reflect that the aliases are gone? Thanks!

@leseb Updated the changelog, PTAL!