typing: fix a syntax error in mercurial/cext/bdiff.pyi
I noticed because `merge-pyi` on the non-cext implementations with this file as
input skipped the return type for this. `pytype-single --parse-pyi` confirmed
it was a problem.
# this file holds the definitions that are used in various bzr tests
TERM=dumb; export TERM
echo '[extensions]' >> $HGRCPATH
echo 'convert = ' >> $HGRCPATH
glog()
{
hg log -G --template '{rev}@{branch} "{desc|firstline}" files+: [{file_adds}], files-: [{file_dels}], files: [{file_mods}]\n' "$@"
}
manifest()
{
echo "% manifest of $2"
hg -R $1 manifest -v -r $2
}