MINOR: ist: add new function ist_find_range() to find a character range

MINOR: ist: add new function ist_find_range() to find a character range

Origin: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=b375df60341c7f7a4904c2d8041a09c66115c754

This looks up the character range <min>..<max> in the input string and
returns a pointer to the first one found. It's essentially the equivalent
of ist_find_ctl() in that it searches by 32 or 64 bits at once, but deals
with a range.

(cherry picked from commit 197668de975e495f0c0f0e4ff51b96203fa9842d)
 [ad: backported for following fix : BUG/MINOR: h2: reject more chars
 from the :path pseudo header]
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit 451ac6628acc4b9eed3260501a49c60d4e4d4e55)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit 3468f7f8e04c9c5ca5c985c7511e05e78fe1eded)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
Gbp-Pq: Name MINOR-ist-add-new-function-ist_find_range-to-find-a-.patch