[Suggestion] Show blue signal post when using route restrictions in 32bpp

[pabloajz]

When using routefinding restrictions in base 8pp graphics, a blue post is displayed in the rail signal.

It seems that is not the case when using 32bpp graphics, either aBase or zBase, being not possible to identify when restrictions are applied to a signal.

It would be quite helpful to add this blue sign (or other mark) to base 32bpp games.