changectx: use names api to simplify and extend node lookup Previously, changectx had to know about each type of name (bookmark, tag, etc.) to look up. Now, we use repo.namenodes to simplify (and extend) this.

namespaces: add a method to the first matching node for a given name

namespaces: add bookmarks to the names data structure This marks the first use of abstracting our different types of named objects (bookmarks, tags, branches, etc.) and upcoming patches will use this to simplify logic.

namespaces: add a convenience property for the weakref _repo

namespaces: pass repo to __init__ We store repo as a weakref so that we can prevent a cycle between namespaces and localrepo.

namespaces: add a function to turn single results into lists

namespaces: add a method to register new namespaces

namespaces: introduce a generic way to map between names and nodes This patch begins the work to provide a way to register a namespace to handle 'names'. Benefits of this would be, - improved templating: This would provide {name} which could output any branch, bookmark, tag, or any extension registered namespace all without having the extension doing any extra work - improved tab completion: Since this provides a single source of all 'names', tab completion would not need to know of each namespace - changeset lookup: Similar to before, a unified place to get all 'names' will allow finding changesets without any extension code having to reimplement this Also, d226fe36e362 has shown us that for internal code which expects a certain type of method or behavior, we should provide an easy way for extensions to check this behavior.