Minor, fix -Wrange-loop-analysis warnings Fixing these complains raised by newer versions of clang, ./hb-ot-layout-common.hh:1720:53: error: loop variable 'gid_klass_pair' is always a copy because the range of type 'hb_map_iter_t<hb_sorted_array_t<OT::HBGlyphID>, (lambda at ./hb-ot-layout-common.hh:1672:29), hb_function_sortedness_t::RETAINS_SORTING, nullptr>' does not return a reference [-Werror,-Wrange-loop-analysis] for (const hb_pair_t<hb_codepoint_t, unsigned>& gid_klass_pair : + it) And ./hb-ot-color-colr-table.hh:177:44: error: loop variable '_' is always a copy because the range of type 'hb_map_iter_t<hb_filter_iter_t<hb_map_iter_t<hb_range_iter_t<unsigned int, unsigned int>, (lambda at ./hb-ot-color-colr-table.hh:209:31), hb_function_sortedness_t::RETAINS_SORTING, nullptr>, (anonymous struct at ./hb-algs.hh:331:1) &, (anonymous struct at ./hb-algs.hh:51:1) &, nullptr>, (anonymous struct at ./hb-algs.hh:338:1) &, hb_function_sortedness_t::RETAINS_SORTING, nullptr>' does not return a reference [-Werror,-Wrange-loop-analysis] for (const hb_item_type<BaseIterator>& _ : + base_it.iter ())