Fix: Make multiple calls to setup() independent

Previously, multiple calls to `gruvbox.setup()` would merge configurations,
leading to unexpected behavior when trying to reset or change specific
settings like `overrides` or `contrast`.

This commit addresses the issue by ensuring that each call to `setup()`
starts with a fresh copy of the default configuration before applying
the user-provided settings.

This change makes calls to `setup()` idempotent and independent of
previous calls, as suggested in issue #402.

A new test case has been added to verify this behavior.

0 files changed, 0 insertions, 0 deletions