Feature request: `colorcolumn` supporting multiple values (only in `settings.json`)

Having multiple highlighted columns is useful in some cases.

For example, Git commit messages usual practice: first line 50 columns, body text 72 columns.

    "ft:git-commit": {
        "colorcolumn": [50, 72]
    },

In Python, the black formatter defaults to 88 columns for code, but for the docstrings and comments, our team prefers breaking them at 80 columns.

    "ft:python": {
        "colorcolumn": [80, 88]
    },

In general, 80 columns is what I like to have, for any other file type.

    "colorcolumn": 80

This is a similar request to the rejected #2694, but my proposal here would be simpler: no new/renamed commands, no user-noticeable changes on the use of set colorcolumn.

We could keep the interactive use as it is, aiming for the simple/common case: set colorcolumn <integer> to set it to a specific column, or zero to turn it off. No changes here.

But, if the user has manually changed the settings.json file and set the value to a list of numbers, those will be respected.

If this makes more sense, maybe it could be valid only for scoped settings (ft: and glob), since those are already not changed by the interactive set command.

Would that be acceptable?

Start by tracing how settings.json values are parsed for scoped ft: and glob settings, then review the interactive set colorcolumn command and its integer and zero-value behavior. Done means list values from settings.json produce multiple highlighted columns while existing interactive behavior remains unchanged.