narrowtemplates: update to use registrar mechanism
It's worth considering at this point if we should just move the two
ellipsis functions to core tagged experimental or something, since
they're not really narrowing-specific...
Differential Revision: https://phab.mercurial-scm.org/D2009
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}