[Misc] Fix some help info of arg_utils to improve readability

[ShangmingCai]

I have noticed some formatting issues in the help info of arg_utils. Specifically, some cases exist where words are connected without spaces when the text wraps to a new line.

For example,

parser.add_argument(
            '--num-gpu-blocks-override',
            type=int,
            default=None,
            help='If specified, ignore GPU profiling result and use this number'
            'of GPU blocks. Used for testing preemption.')

So I fix all I can find.

cc @DarkLight1337

[github-actions]

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[DarkLight1337]

Thanks for the QoL improvement!