copies: define a type to return from mergecopies()...
copies: define a type to return from mergecopies()
We'll soon return two instances of many of the dicts from
`copies.mergecopies()`. That will mean that we need to return 9
different dicts, which is clearly not manageable. This patch instead
encapsulates the 4 dicts we'll duplicate in a new type. For now, we
still just return one instance of it (plus the separate `diverge`
dict).
Differential Revision:
https://phab.mercurial-scm.org/D7989
