Robot Framework lexer: Fixed handlign trailing spaces.
Robot Framework lexer: Fixed handlign trailing spaces.

Fixes Pygments bug #855:
https://bitbucket.org/birkenfeld/pygments-main/issue/855/robot-framework-lexer-returns-wrong

sol/pygments,zmughal/pygments-mirror,sol/pygments,zmughal/pygments-mirror,sol/pygments,zmughal/pygments-mirror,zmughal/pygments-mirror,sol/pygments,sol/pygments,sol/pygments,zmughal/pygments-mirror,sol/pygments,sol/pygments,zmughal/pygments-mirror,zmughal/pygments-mirror,sol/pygments,sol/pygments,zmughal/pygments-mirror,sol/pygments,sol/pygments,zmughal/pygments-mirror,zmughal/pygments-mirror,zmughal/pygments-mirror,zmughal/pygments-mirror,zmughal/pygments-mirror,zmughal/pygments-mirror,sol/pygments,zmughal/pygments-mirror,zmughal/pygments-mirror,zmughal/pygments-mirror,sol/pygments,zmughal/pygments-mirror,zmughal/pygments-mirror