histedit: use `get_unique_push_path` Same as for `pathbomb`, this code does not support multiple destinations yet. It might in the future, probably with code put in common with patchwork, but for now lets use the dedicated API. Differential Revision: https://phab.mercurial-scm.org/D10408

urlutil: add a new `get_unique_push_path` This function is dedicated to call that needs a single destination. Currently most caller actually need that since few actually support multiple destinations (the most importants `hg push` and `hg outgoing` do). So having a clear API point for that will be important when the time comes to have a single `[paths]` alias resolving to multiple urls. Differential Revision: https://phab.mercurial-scm.org/D10407

fetch: use `get_unique_pull_path` to retrieve the path The fetch command does not support multiple destination, so we use the new dedicated API for that. Differential Revision: https://phab.mercurial-scm.org/D10406

patchbomb: use `get_unique_pull_path` The patchbomb code does not support multiple destinations yet. It would not be too hard to implemented since `hg outgoing` does. However that is a bit too much of a detour right now. In addition that kind of "select outgoing changesets for processing" code exist for various commands so the best would be to factor it out later. Let us use the dedicated API until this is solved. This comes with a small output change in the test that I find more accurate. So I kept it. Differential Revision: https://phab.mercurial-scm.org/D10405

narrow: use `get_unique_pull_path` The narrow's `tracked` command does not support multiple destination, lets use the dedicated API then. Differential Revision: https://phab.mercurial-scm.org/D10404

urlutil: add a new `get_unique_pull_path` This function is dedicated to call that needs a single destination. Currently most caller actually need that since few actually support multiple destinations (the most importants `hg push` and `hg outgoing` do). So having a clear API point for that will be important when the time comes to have a single `[paths]` alias resolving to multiple urls. Differential Revision: https://phab.mercurial-scm.org/D10403

mq: use the new `get_clone_path` to get the remote url We stop using `ui.expandpath` to use a function with a more defined semantic. This will help us to make it an option to point [paths] entry to multiple destination. Differential Revision: https://phab.mercurial-scm.org/D10402