paper/coal: use fixed width for diffstat +/- link
The plus and minus characters are normally not the same width in a
non-monospace font, and this made the line length change when the
diffstat display was toggled.
The square brackets are not rendered in a monospace font to ensure
that they align with the parenthesis on the same line.
changeset = '{rev}{tags}{bookmarks}{parents} {node|short} {date|isodate} {author|user}\n {desc|firstline|strip}\n\n'
changeset_quiet = '{rev}:{node|short}\n'
changeset_verbose = '{rev}{tags}{parents} {node|short} {date|isodate} {author}\n {desc|strip}\n\n'
start_tags = '['
tag = '{tag},'
last_tag = '{tag}]'
start_parents = ':'
parent = '{rev},'
last_parent = '{rev}'
start_bookmarks = '['
bookmark = '{bookmark},'
last_bookmark = '{bookmark}]'