Forbid var usage
Forbid var usage

Add style check to forbid var usage[0]. There is no JSCS equivalent of
prefer-const[1].

[0] http://jscs.info/rule/disallowVar
[1] http://jscs.info/rules?q=const

Change-Id: I95a9cce9f58dd883670e6694b25da606b130313e

wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps