copies: replace duplicatecopies() by function that takes contexts
The callers mostly have context objects, so let's avoid looking up the
same context objects inside `duplicatecopies()`.
I also renamed the function to `graftcopies()` since I think that
better matches its purpose. I did it in the same commit so it's easier
for extensions to switch between the functions.
Differential Revision: https://phab.mercurial-scm.org/D7858
{
// 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)
}