template-phases: extend default style instead of duplicating it
The phases style started as a copy of the default style at 5c5152af0d15, but
we didn't have to copy it because the templater supports %include syntax.
This makes sure that the phases style have the same output as the default
except for the additional "phase:" row.
%include map-cmdline.default
changeset = '{cset}{branches}{bookmarks}{tags}{lphase}{parents}{user}{ldate}{summary}\n'
changeset_verbose = '{cset}{branches}{bookmarks}{tags}{lphase}{parents}{user}{ldate}{lfiles}{lfile_copies_switch}{description}\n'