patchlog doc: the argument to --encoding is not optional

>  $ git log --encoding
>  fatal: Option '--encoding' requires a value
>  $ git rev-list --encoding
>  fatal: Option '--encoding' requires a value
>
> The argument to --encoding has always been mandatory.  Unfortunately
> manpages like git-rev-list(1), git-log(1), and git-show(1) have
> described the option's syntax as "--encoding[=<encoding>]" since it
> was first documented.  Clarify by removing the extra brackets.
>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---

>  Documentation/git-rev-list.txt   | 2 +-
>  Documentation/pretty-options.txt | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt
> index 65ac27e0..045b37b8 100644
> --- a/Documentation/git-rev-list.txt
> +++ b/Documentation/git-rev-list.txt
> @@ -40,7 +40,7 @@ SYNOPSIS
>  	     [ \--right-only ]
>  	     [ \--cherry-mark ]
>  	     [ \--cherry-pick ]
> -	     [ \--encoding[=<encoding>] ]
> +	     [ \--encoding=<encoding> ]
>  	     [ \--(author|committer|grep)=<pattern> ]
>  	     [ \--regexp-ignore-case | -i ]
>  	     [ \--extended-regexp | -E ]
> diff --git a/Documentation/pretty-options.txt b/Documentation/pretty-options.txt
> index 5e499421..eea0e306 100644
> --- a/Documentation/pretty-options.txt
> +++ b/Documentation/pretty-options.txt
> @@ -28,7 +28,7 @@ people using 80-column terminals.
>  	This is a shorthand for "--pretty=oneline --abbrev-commit"
>  	used together.
>  
> ---encoding[=<encoding>]::
> +--encoding=<encoding>::
>  	The commit objects record the encoding used for the log message
>  	in their encoding header; this option can be used to tell the
>  	command to re-code the commit log message in the encoding