Determine how to convey the availablity of preview-only fixes

[zanieb]

We intend for some fixes to only be available in preview, e.g. #8073 and #7934 but then rules will be displayed as fixable in the documentation without indication that it is only fixable with preview enabled. We worry this will be confusing.

[Avasam]

I was just about to open a new issue about a rule being documented with "Fix is always available." (https://docs.astral.sh/ruff/rules/unnecessary-builtin-import/).

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On the rule page itself, I think you could have:
"Fix is always available" / "Fix is sometimes available" / (no fix available)
and separately mention that "Some fixes are marked unsafe by default"

I don't think it's necessary to mention that "All fixes are unsafe". But at a user I wouldn't mind being a touch more exact. As long as it is show that I need to run --unsafe-fixes to get all the available fixes.

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As for the "all rules" page.
You could differentiate between "sometimes autofixable" and "always autofixable" with 🔨 or 🔧, it's visually just 🛠️ but with a tool missing. I personally quite like that.

As for fix safety, I'm less certain of the best way to display that / convey the information concisely. I think that adding a column should be fine.
The first thing that comes to mind is ⚠️, but it looks out of place/scary even when grayed out:

Other suggestions may include ⁉, 🚦, or just annotating the autofix with *, or even get fancy with it with a set-width column (or a 0-width element translated to the right position):