Add --line-number option to hg annotate (issue506) Line numbers are separated from the last annotation element with a colon, like with many other commands, e.g. (hg) grep or compiler errors. Idea and tests by FUJIWARA Katsunori.

% basic
% unknown
*** [alias] unknown: command bargle is unknown
% ambiguous
*** [alias] ambiguous: command s is ambiguous
% recursive
*** [alias] recursive: circular dependency on recursive
adding foo
% with opts
C foo