user-manual: use 'remote add' to setup push URLs

There is no need to use here documents to setup this configuration.
It is easier, less confusing, and more robust to use `git remote add`
directly.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
user-manual: give 'git push -f' as an alternative to +master

This mirrors existing language in the description of 'git fetch'.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
user-manual: mention 'git remote add' for remote branch config

I hardly ever setup remote.<name>.url using 'git config'.  While it
may be instructive to do so, we should also point out 'git remote
add'.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
user-manual: use 'git config --global user.*' for setup

A simple command line call is easier than spawning an editor,
especially for folks new to ideas like the "command line" and "text
editors".  This is also the approach suggested by 'git commit' if you
try and commit without having configured user.name or user.email.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
user-manual: use -o latest.tar.gz to create a gzipped tarball

This functionality was introduced by 0e804e09 (archive: provide
builtin .tar.gz filter, 2011-07-21) for v1.7.7.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>