Re: [PATCH 13/20] userdiff tests + docs: document & test "diff.<driver>.x?funcname"

> Add the missing documentation for "diff.<driver>.funcname" and test
> for how it and "diff.<driver>.xfuncname" interact.
> [...]
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
> diff --git a/Documentation/config/diff.txt b/Documentation/config/diff.txt
> @@ -153,10 +153,22 @@ diff.<driver>.command::
> +diff.<driver>.funcname::
>  diff.<driver>.xfuncname::
>         The regular expression that the diff driver should use to
>         recognize the hunk header.  A built-in pattern may also be used.
>         See linkgit:gitattributes[5] for details.
> ++
> +When provided as `diff.<driver>.funcname` the regular expression is
> +interpreted as a basic regular expression, with

> +`diff.<driver>.xfuncname` it's interpreted as an extended regular
> +expression.
> ++
> +
> +The `*.funcname` and `*.xfuncname` variables behave as if though they
> +were one configuration variable for the purposes of what value
> +eventually gets used. Setting `*.funcname` will override an earlier
> +`*.xfuncname` and vice-versa.