copies: prepare changelog for more copies storage mode
We want to store copies information in sidedata, the logic will be quite similar
to the one used for extra, but sightly different (not in extra, no hash impact).
We start with small refactoring to make our work easier and the coming changesets
cleaners.
Differential Revision: https://phab.mercurial-scm.org/D6936
{
// 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)
}