[PATCH 0 of 2 V2] keyword: document additional datefilters and offer them on load

[Christian Ebert]

Hi,

Patrick made the additional keyword datefilters ready for
docstring generation, so here's a proposal for their wording,
improvements by native speakers are of course welcome.

The 2nd patch adds them when the extension is loaded so they can
be used outside the kwtemplater class and appear in the output of
"hg help templates":

$ hg showconfig extensions | fgrep keyword
extensions.keyword=
$ hg help templates | egrep -A 1 'utcdate|svnisodate'
    svnisodate  Date. Returns a date in this format: "2009-08-18 13:00:13
                +0200 (Tue, 18 Aug 2009)".
    svnutcdate  Date. Returns a UTC-date in this format: "2009-08-18
                11:00:13Z".
--
    utcdate     Date. Returns a UTC-date in this format: "2009/08/18
                11:00:13".


c