repoview: add visibilityexceptions as an optional argument to repo.filtered() This will help us in having an API where we can pass the filtername and the visibilityexceptions to get a new repo object. Visibility exceptions are the revs which must be visible even they should in theory belong to the hidden set. They are required as there has been desire to have a functionality to access hidden changesets using certain commands without passing --hidden. After this patch we can make those changesets visibility exceptions so that we can access them without requiring a unfiltered repo. Differential Revision: https://phab.mercurial-scm.org/D1746