help/dates: use DATE as place-holder in help and abort texts
The use of "{datetime}" was unfortunate since I as a user never knew
if I was expected to do
hg log -d '>{2011-04-01}'
or
hg log -d '>2011-04-01'
The word "datetime" is also confusing -- calling it a date it much
simpler.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.