tests/histedit-helpers.sh

graft: clarify in help that `-r` is not just optional

Positional parameters are also treated as revisions, but the order of revisions
matters and it will often be wrong if the user understands it as `-r` taking
multiple revisions as `-r REV1 REV2`.

(Alternatively, `-r` could be turned into a no-op flag as the documentation
suggests. That would however be less "semantic markup" and I agree with the
implementation in 55e7f352b1d3 but not the documentation.)

fixbundle() {
    grep -v 'saving bundle' | grep -v 'saved backup' | \
        grep -v added | grep -v adding | \
        grep -v "unable to find 'e' for patching" | \
        grep -v "e: No such file or directory" | \
    cat
}