…er editor configuration (#11086)

## Summary

This is intended to address
astral-sh/ruff-vscode#425, and is a follow-up
to #11062.

A new client setting is now supported by the server,
`prioritizeFileConfiguration`. This is a boolean setting (default:
`false`) that, if set to `true`, will instruct the configuration
resolver to prioritize file configuration (aka discovered TOML files)
over configuration passed in by the editor.

A corresponding extension PR has been opened, which makes this setting
available for VS Code:
astral-sh/ruff-vscode#457.

## Test Plan

To test this with VS Code, you'll need to check out [the VS Code
PR](astral-sh/ruff-vscode#457) that adds this
setting.

The test process is similar to
#11062, but in scenarios where the
editor configuration would take priority over file configuration, file
configuration should take priority.

)

## Summary

Fixes #425 (though only
in the pre-release version, since this is a feature for the new LSP
server)

This is a follow-up to
#456.

A new setting has been introduced, `Prioritize File Configuration`,
which tells the extension to prioritize settings from discovered TOML
files over extension settings. Extension settings will still be used
when a set field in the extension is not set in the file configuration.

## Test Plan

Refer to astral-sh/ruff#11086 for a test plan.