[pcre-dev] Supplement docs about partial match

Hello!


Chapter ISSUES WITH MULTI-SEGMENT MATCHING of pcre2partial.html includes
item 2 with description how to process with lookbehind assertions.

I think it's important to add to this algorithm a some words about "no
match":
If result of partial match is "no match" then last max_lookbehind
characters of subject string must be keeped to next matching too. Matching
of next segment must start with appropriate offset.


Thanks.