Added known issue for missing child context in sections.
Added known issue for missing child context in sections.

BrunoDeBarros/mustache.php,evdevgit/mustache.php,sophatvathana/mustache.php,cgvarela/mustache.php,ericariyanto/mustache.php,thecocce/mustache.php,bobthecow/mustache.php,daffl/zfmustache,zuluf/mustache.php,irontec/mustache