[texdoc] `texdoc changes` opens .../generic/xint/CHANGES.pdf instead of .../latex/changes/changes.english.pdf

[Karl Berry]

    Subject: [texdoc] `texdoc changes` opens .../generic/xint/CHANGES.pdf
            instead of .../latex/changes/changes.english.pdf

Thanks Denis.  I seem to recall a discussion with Manuel about making a
name match at the "package level" (/changes/) be preferred to a match
only at the "file level" (CHANGES.pdf).  Not sure if there would be bad
unintended consequences.  Anyway, maybe we'll be able to try it at some
point.  For now, can at least put in a special case for "changes".

Thanks,
K