Change ratio ruler values on workspace guides
Summary:
Seems not possible to change the ratio in the ruler in the inkscape workspace, talking with @doctormo those values are hardcoded https://gitlab.com/inkscape/inkscape/-/blob/master/src/ui/widget/ink-ruler.cpp#L29
The user case is that as I am working with printers and laser engraver those values are not helpful to position the various elements and understand the size etc as they are on 5 base instead it would better to have like 0-20-40-60 in this way it is more easy to put guides and understand the various size.
Reading the code in the inch case they are on base 2 that is more easy as it is even value, maybe adding a setting for this will improve the usage as compile inkscape for the various machine I have between Windows/Linux is not so suitable for my work (just to change those values).
Just for comparison also on GIMP there is this issue as they are too on that 5 base and I don't see a setting parameter for that