Internals: clarified the code for ClampWindowRect().
Internals: clarified the code for ClampWindowRect().

As a side-effect, some rounding error may be neutralized however this isn't the intent. (#3309)

ggtucker/imgui,Flix01/imgui,ggtucker/imgui,Flix01/imgui,ocornut/imgui,nProtect/imgui,bkaradzic/imgui,ggtucker/imgui,Flix01/imgui,aimotive/imgui-glfw,nProtect/imgui,ocornut/imgui,bkaradzic/imgui,aimotive/imgui-glfw,ocornut/imgui,nProtect/imgui,bkaradzic/imgui