Use DIFF_DETECT_RENAME for detect_rename assignments

This field can have two values (2 for copy). Use this name instead for
clarity. Many places have already used this constant.

Note, the detect_rename assignments in merge-recursive.c remain
unchanged because it's actually a boolean there.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/commit.c

@@ -1473,7 +1473,7 @@ static void print_summary(const char *prefix, const struct object_id *oid,
 	rev.show_root_diff = 1;
 	get_commit_format(format.buf, &rev);
 	rev.always_show_header = 0;
-	rev.diffopt.detect_rename = 1;
+	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 

diff.c

@@ -218,7 +218,7 @@ static int parse_ws_error_highlight(const char *arg)
  */
 void init_diff_ui_defaults(void)
 {
-	diff_detect_rename_default = 1;
+	diff_detect_rename_default = DIFF_DETECT_RENAME;
 }
 
 int git_diff_heuristic_config(const char *var, const char *value, void *cb)

wt-status.c

@@ -603,7 +603,7 @@ static void wt_status_collect_changes_index(struct wt_status *s)
 	rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 	rev.diffopt.format_callback = wt_status_collect_updated_cb;
 	rev.diffopt.format_callback_data = s;
-	rev.diffopt.detect_rename = 1;
+	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
 	rev.diffopt.rename_limit = 200;
 	rev.diffopt.break_opt = 0;
 	copy_pathspec(&rev.prune_data, &s->pathspec);
@@ -937,7 +937,7 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
-	rev.diffopt.detect_rename = 1;
+	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
 	rev.diffopt.file = s->fp;
 	rev.diffopt.close_file = 0;
 	/*