man: string: document BM false negatives

For non-linear skb's there's a possibility that the kernel's Boyer-Moore
text-search implementation may miss matches.  There's a warning about
this in the kernel source.  Include that warning in the man-page.

Link: https://bugzilla.netfilter.org/show_bug.cgi?id=1390
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Phil Sutter <phil@nwl.cc>
1 file changed