rank: naive rank property computation and retrieval
This stores the rank (size of the ancestor set of a revision, including itself)
in a changelog field and allows this property to be retrieved.
This new property is used as part of stable-range computations, which will be
introduced later on.
The value is computed in a naive way from the definition of the rank. This will
be replaced by a more efficient version subsequently.
Differential Revision: https://phab.mercurial-scm.org/D12139
{
// 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)
}