Fixed typo in rtl-hook devGuide section.
Merge branch 'rtl-hook-typo-fix' of https://github.com/mwilliams2014/liferay-docs into lr-pr-70-rtl-hook-type-fix
Merge pull request #1017 from jhinkey/lr-pr-70-rtl-hook-type-fix

RTL hook typo fix in Dev Guide