Add a ReshadeEffectShaderToggler guide

[originalnicodr]

A fork made out of ShaderToggler called ReshadeEffectShaderToggler allows us to apply Reshade effects to render targets before specific vanilla-game shaders, meaning that you can use shaders like ambient occlusion before smoke or bloom, which is very useful for screenshots.

It shouldn't be much different from ShaderToggler regarding how to use it, but it would be cool for someone to check it out and write something quick about it, to at least shine a little light on it.