Author: Dan Poltawski
MDL-46591 filter_tex: improved string
Thanks to German Valero for noticing this and Matteo Scaramuccia, Daniel
Thies and Helen Foser for refining it.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ff7efc55ecc438694d4d517430acf95fa896ec23
http://github.com/moodle/moodle/commit/ff7efc55ecc438694d4d517430acf95fa896ec23
+ 2.8 en [configconvertformat,filter_tex]