This is not the correct fix, the correct one is simply to change:

Target="https://nodejs.org/download/$(var.DistTypeDir)/v$(var.FullVersion)/doc/api/"

Target="https://nodejs.org/download/$(var.DistTypeDir)/v$(var.FullVersion)/docs/api/"

i.e. docs not doc

It's intended to work for all release types, not just general releases but also nightlies, release candidates etc.