[PATCH tig] Fix compiler warning with latest gcc

[Marcel Holtmann <marcel@holtmann.org>]

        CC  src/diff.o
src/diff.c: In function ‘diff_common_add_diff_stat’:
src/diff.c:191:22: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  191 |         char *pipe = strchr(data, '|');
      |                      ^~~~~~
---
 src/diff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/diff.c b/src/diff.c
index 6c670e4b4fb4..182ea349eb9c 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -188,7 +188,7 @@ diff_common_add_diff_stat(struct view *view, const char *text, size_t offset)
 	const char *start = text + offset;
 	const char *data = start + strspn(start, " ");
 	size_t len = strlen(data);
-	char *pipe = strchr(data, '|');
+	const char *pipe = strchr(data, '|');
 
 	/* Ensure that '|' is present and the file name part contains
 	 * non-space characters. */
-- 
2.53.0