Range modifier notes

• The Snort/PCRE R option is no longer part of our PCRE. Use --distance 0; instead.
• If you do not use a range modifier with pattern or pcre, matching is done from the beginning to the end of the buffer.
• If you only use distance or distance_abs with pattern or pcre, matching is done from the location that is relative to the reference specified by <refer> to the end of the buffer.