diff --stat: add config option to limit filename width

Add new configuration option diff.statNameWidth=<width> that is equivalent
to the command-line option --stat-name-width=<width>, but it is ignored
by format-patch.  This follows the logic established by the already
existing configuration option diff.statGraphWidth=<width>.

Limiting the widths of names and graphs in the --stat output makes sense
for interactive work on wide terminals with many columns, hence the support
for these configuration options.  They don't affect format-patch because
it already adheres to the traditional 80-column standard.

Update the documentation and add more tests to cover new configuration
option diff.statNameWidth=<width>.  While there, perform a few minor code
and whitespace cleanups here and there, as spotted.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/config/diff.txt b/Documentation/config/diff.txt
index 35a7bf86d7..9391c77e55 100644
--- a/Documentation/config/diff.txt
+++ b/Documentation/config/diff.txt
@@ -52,6 +52,10 @@ directories with less than 10% of the total amount of changed files,
 and accumulating child directory counts in the parent directories:
 `files,10,cumulative`.
 
+diff.statNameWidth::
+	Limit the width of the filename part in --stat output. If set, applies
+	to all commands generating --stat output except format-patch.
+
 diff.statGraphWidth::
 	Limit the width of the graph part in --stat output. If set, applies
 	to all commands generating --stat output except format-patch.