[PATCH STABLE] log: mention ui.logtemplate in the help text

[Jun Wu]

LGTM.

Excerpts from Nathan Goldbaum's message of 2017-08-16 10:26:08 -0500:
> # HG changeset patch
> # User Nathan Goldbaum <ngoldbau at illinois.edu>
> # Date 1502897089 18000
> #      Wed Aug 16 10:24:49 2017 -0500
> # Branch stable
> # Node ID a1db17e964beee1a839769507818a50a5de3c9a3
> # Parent  7686cbb0ba4138c56d038d8d82ccc052bf9b60d7
> log: mention ui.logtemplate in the help text
> 
> diff --git a/mercurial/commands.py b/mercurial/commands.py
> --- a/mercurial/commands.py
> +++ b/mercurial/commands.py
> @@ -3335,7 +3335,9 @@ def log(ui, repo, *pats, **opts):
>      revisions.
>  
>      See :hg:`help templates` for more about pre-packaged styles and
> -    specifying custom templates.
> +    specifying custom templates. The default template used by the log
> +    command can be customized via the ``ui.logtemplate`` configuration
> +    setting.
>  
>      Returns 0 on success.
>