the issue was that PR references in kanban boards were being generated
using `.ID` instead of `.Index`, which led to constructing incorrect
links to possibly non-existent {PR,issue}s and following that to showing
nonsensical values in the boards.
kudos also go to @zeripath for pointing at the file to fix.
Signed-off-by: wULLSnpAXbWZGYDYyhWTKKspEQoaYxXyhoisqHf <a_mirre@utb.cz>
Co-authored-by: zeripath <art27@cantab.net>