A large negative return code doesn't do a human reader any good, even for
lookup purposes, because Microsoft's lookup tables list the hex representation
of that integer. So at least format the return code as hex.
Going further, we've captured the content of the web page
https://msdn.microsoft.com/en-us/library/cc704588.aspx
as windows-rcs.html. If we can parse that file, and if we understand the
structure of its table entries, and if the hex form of the actual return code
is in fact listed there, we can display the symbol name and description as
well as the hex return code.
All those maybes are to support refreshing the file from the URL above (or
wherever it might get moved) from time to time. Later versions of that file
might change in unexpected ways.
If we can't look up the hex rc, oh well, just display that to the user instead
of crumping.