hghave: list the module needed for the `vcr` check I'm tired of having to look up modules each time I setup a system, and try to distinguish between similar package names to get the right one. Now that the search API has been disabled, it's even harder. There are other python packages here that should be listed like this, but this is the one that came up missing today, so it's a start. Differential Revision: https://phab.mercurial-scm.org/D9879