fix: show_signature now ignores trigger.enabled if called directly

[dladukedev]

Current State - Calling show_signature() when signature.enabled = true but signature.trigger.enabled = false prevents the signature popup from showing at all.

Expected State - Calling show_signature() directly (similar to show()) should ignore the signature.trigger.enabled flag

Change - Add a force opt to match show() that bypasses the signature.trigger.enabled flag