Running %ai help yields %%ai help twice

[JasonWeill]

Description

After #188 was merged in, running %ai help results in the %%ai command being described twice:

Usage: %%ai [OPTIONS] MODEL_ID

  Invokes a language model identified by MODEL_ID, with the prompt being
  contained in all lines after the first. Both local model IDs and global
  model IDs (with the provider ID explicitly prefixed, followed by a colon)
  are accepted.

  To view available language models, please run `%ai list`.

Options:
  -f, --format [code|html|image|json|markdown|math|md|text]
                                  IPython display to use when rendering
                                  output. [default="markdown"]
  -r, --reset                     Clears the conversation transcript used when
                                  interacting with an OpenAI chat model
                                  provider. Does nothing with other providers.
  --help                          Show this message and exit.
------------------------------------------------------------------------------
Usage: %%ai [OPTIONS] MODEL_ID

  Invokes a language model identified by MODEL_ID, with the prompt being
  contained in all lines after the first. Both local model IDs and global
  model IDs (with the provider ID explicitly prefixed, followed by a colon)
  are accepted.

  To view available language models, please run `%ai list`.

Options:
  -f, --format [code|html|image|json|markdown|math|md|text]
                                  IPython display to use when rendering
                                  output. [default="markdown"]
  -r, --reset                     Clears the conversation transcript used when
                                  interacting with an OpenAI chat model
                                  provider. Does nothing with other providers.
  --help                          Show this message and exit.
------------------------------------------------------------------------------
Usage: %ai [OPTIONS] COMMAND [ARGS]...

  Invokes a subcommand.

Options:
  --help  Show this message and exit.

Commands:
  help  Show this message and exit.
  list  List language models. See `%ai list --help` for options.