Include settings path in --show-settings

[charliermarsh]

We should tell you which settings file was loaded on-disk.

[charliermarsh]

This is surprisingly difficult (or, at least, requires some refactoring).

[dhruvmanila]

I think I can take this up tomorrow, have been looking at the CLI code recently.

One doubt is what to output when ran in --isolated mode or using the default settings as a fallback. Maybe don't include the path or leave it blank like "-":

https://github.com/charliermarsh/ruff/blob/333f1bd9ceff6390ae652790abb22cd175042bc7/crates/ruff_cli/src/resolve.rs#L65-L72

The output I'm thinking of:

$ ruff check --show-settings .
Resolved settings for: "..."
Settings path: "..."
Settings {
    rules: RuleTable {
        enabled: {
			...