[web-annotation] Issue: The textDirection and processingLanguage properties are not needed marked as i18n-review

r12a has just labeled an issue for 
https://github.com/w3c/web-annotation as "i18n-review":

== The textDirection and processingLanguage properties are not needed 
==
These are both simplistic assertions about an external resource that 
provide no useful information to a user or a user-agent.
An external resource can have multiple text directions, and languages;
 attempting to boil these down to one is not practical in general. See
 http://unicode.org/reports/tr9/ for the nuances of text direction  

See https://github.com/w3c/web-annotation/issues/335