P: azerty keyboard shortcut for \ (backslash- show and hide overlay mask) - make it assignable

https://forums.adobe.com/thread/2628101

I am having an issue with displaying layer overlay, as I am working on a WIN10, PS CC machine, but I am based in Belgium (and using azerty keyboard) and therefor, I cannot reach the \ shortcut.  For me, that is ALT GR+<, which PS does not recognize.  It is driving me crazy! I have read articles and understand the menu shortcut is hidden (that is why I have just spent the last hour searching for it in vain, before I found this article).

 

I have also had to change "change brush size" in order to use my wacom intuos pro tablet some years ago (from "[" or "{" and "]" or "}" to "(" and ")". Does someone know how I can display the mask overlay (in ruby red, as Adobe calls it) for my machine?  Reading the above, I don't fancy changing my keyboard just for PS and having to change it afterwards every time, as I often switch between browsing, emails, PS and LR.

 

My question is thus : Make the backslash key for showing/hiding the mask overlay assignable to another key in Photoshop.