Improve parsing & formatting of help page descriptions

[lgarber-akamai]

📝 Description

This pull request resolves various issues that caused help page argument descriptions to not be properly parsed, leading to malformed outputs like:

--label (required): A unique.

✔️ How to Test

The following test steps assume you have pulled down this PR locally and run make install.

Unit Testing

make testunit

Manual Testing

1. In your linode-cli project directory, create a new dump_descriptions.py file with the following contents:

from linodecli import CLI
from rich.console import Console

from linodecli.baked.request import OpenAPIRequestArg

console = Console()

cli = CLI("0.0.0.dev", "https://localhost", skip_config=True)

cli.load_baked()

for op_name, op in cli.ops.items():
    for action_name, action in op.items():
        console.print(f"[green b]{op_name} {action_name}[/green b]: {action.summary}")

        if action.request is None:
            console.print()
            continue

        for arg in action.request.attrs:
            if not isinstance(arg, OpenAPIRequestArg):
                continue

            console.print(f"\t[blue b]--{arg.name}[/blue b]: {arg.description_rich}")

        console.print()

2. Run python3 dump_descriptions.py.
3. Manually review the output and ensure all descriptions are readable and do not have any formatting issues.

[lgarber-akamai]

We don't consume OpenAPIOperation(...).description currently but I figured it'd be good to future-proof 🙂

[lgarber-akamai]

The changes in this file originated in #639, which provides a bit more context for why they were made.

[ezilber-akamai]

Thanks for fixing this! Unit tests are passing locally and manual test looked good too.