Better output for toolkit CLI difference

[me-diru]

The changes observed between the two versions of spin CLI are shown using CLI output script.

It seems tedious to figure out under which subcommand the flags belong, and I had to do a bit of trial-and-error. Maybe a better output, along with the subcommand where the flags were changed, might be helpful.

For reference #1358

From

< Output: spin 2.6.0 (a4ddd39 2024-06-20)
---
> Output: spin 2.7.0 (a111517 2024-07-30)
47a48,50
>         --allow-overwrite              If the output directory already contains files, generate the
>                                        new files into it without confirming, overwriting any
>                                        existing files with the same names
890a894,896
>         --allow-overwrite              If the output directory already contains files, generate the
>                                        new files into it without confirming, overwriting any
>                                        existing files with the same names
974a981
>         --all                List all versions of plugins. This is the default behaviour
977a985
>         --summary            List latest and installed versions of plugins
1273,1274c1281,1283
<                                    a directory containing a spin.toml file, or a remote registry
<                                    reference. If omitted, it defaults to "spin.toml"
---
>                                    a directory containing a spin.toml file, a remote registry
>                                    reference, or a Wasm module (a .wasm file). If omitted, it
>                                    defaults to "spin.toml"

To

< Output: spin 2.6.0 (a4ddd39 2024-06-20)
---
> Output: spin 2.7.0 (a111517 2024-07-30)
47a48,50
>         spin add --allow-overwrite              If the output directory already contains files, generate the
>                                        new files into it without confirming, overwriting any
>                                        existing files with the same names
890a894,896
>         spin new --allow-overwrite              If the output directory already contains files, generate the
>                                        new files into it without confirming, overwriting any
>                                        existing files with the same names
974a981
>         spin plugins list --all                List all versions of plugins. This is the default behaviour
977a985
>         spin plugins list --summary            List latest and installed versions of plugins
1273,1274c1281,1283
<                                    a directory containing a spin.toml file, or a remote registry
<                                    reference. If omitted, it defaults to "spin.toml"
---
>                                    a directory containing a spin.toml file, a remote registry
>                                    reference, or a Wasm module (a .wasm file). If omitted, it
>                                    defaults to "spin.toml"