Fix "declaration of 'error' hides function parameter" warnings

[JCash]

From the build logs here: https://github.com/JCash/Remotery/runs/6932216784?check_suite_focus=true

lib\Remotery.c(497): warning C4457: declaration of 'error' hides function parameter
lib\Remotery.c(488): note: see declaration of 'error'
lib\Remotery.c(3728): warning C4456: declaration of 'error' hides previous local declaration
lib\Remotery.c(3714): note: see declaration of 'error'
lib\Remotery.c(3953): warning C4456: declaration of 'error' hides previous local declaration
lib\Remotery.c(3935): note: see declaration of 'error'