Author: Eric Merrill
MDL-53612 search: Add book chapter search area
http://git.moodle.org/gw?p=moodle.git;a=commit;h=cdb9e8db738e92d6ad0acee2ed08a6ba32d69e10
http://github.com/moodle/moodle/commit/cdb9e8db738e92d6ad0acee2ed08a6ba32d69e10
+ 3.1 en [search:chapter,mod_book]