Extract load_branch_decorations from todo_list_add_update_ref_commands so
it can be re-used in make_script_with_merges.

Since it can now be called multiple times, use non-static lists and place
it next to load_ref_decorations to re-use the decoration_loaded guard.

Signed-off-by: Nicolas Guichard <redacted>
---

diff --git a/log-tree.c b/log-tree.c

@@ -248,6 +248,27 @@ void load_ref_decorations(struct decoration_filter *filter, int flags)
+void load_branch_decorations(void)
+{
+       if (!decoration_loaded) {
+               struct string_list decorate_refs_exclude = STRING_LIST_INIT_NODUP;
+               struct string_list decorate_refs_exclude_config = STRING_LIST_INIT_NODUP;
+               struct string_list decorate_refs_include = STRING_LIST_INIT_NODUP;
+               struct decoration_filter decoration_filter = {
+                       .include_ref_pattern = &decorate_refs_include,
+                       .exclude_ref_pattern = &decorate_refs_exclude,
+                       .exclude_ref_config_pattern = &decorate_refs_exclude_config,
+               };
+
+               string_list_append(&decorate_refs_include, "refs/heads/");
+               load_ref_decorations(&decoration_filter, 0);
+
+               string_list_clear(&decorate_refs_exclude, false);
+               string_list_clear(&decorate_refs_exclude_config, false);
+               string_list_clear(&decorate_refs_include, false);
+       }