copies: rename diverge2 to divergeset for clarity

copies: begin separating mergecopies sides

copies: rename ctx() to getfctx() for clarity

monoblue: port code selection without line numbers from gitweb This is adapted from 2239626369f5. It also fixes issue4790 in monoblue; tab characters now have meaningful width on the modified pages (file view, file diff, changeset).

help: copy-edit description of ui.supportcontact

ui: avoid mutable default arguments I almost introduced a bug around this code by accidentally mutating a default argument. There's no reason for these to exist. It is OK to not assign {} to environ in ui.system because util.system knows how to deal with that.

util: avoid mutable default arguments I almost introduced a bug around this code by accidentally mutating a default argument. There's no reason for these to exist.

obsstore: fast path to check if obsstore is empty

obsstore: delay loading markers from obsstore file This will allow us to use cached revisions without parsing obsstore. Because _version isn't determined at __init__, the debugobsconvert command no longer works correctly. I'll fix it by a separate patch for the evolve extension.

obsstore: initialize _all markers without using _addmarkers() The next patch will make _all variable propertycached to avoid costly parsing of obsstore. This means we can't call _addmarkers() to initialize _all. Because all cached markers depend on _all, it isn't necessary to update these caches when _all is initially loaded.