log-tree.c: Use struct name_decoration's type for classifying decoration The "tag: " prefix is no longer prepended to the name of the decoration. It is now printed conditionally by show_decorations if the decoration type is DECORATION_REF_TAG. Signed-off-by: Nazri Ramliy <ayiehere@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>