filemerge: work with `simplemerge.MergeInput` in `filemerge()`
We currently pass around pairs of file context objects and labels
between functions in the `filemerge` module. I plan to pass around
`simplemerge.MergeInput` instead. This patch prepares for that by
using the type internally in `filemerge.filemerge()`.
Differential Revision: https://phab.mercurial-scm.org/D12017
{
// 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)
}