copies: move debug statement to appropriate place

bidmerge: choose shortest list of diverge and rename/delete warnings Slightly less arbitrary than choosing the first set.

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.