Improve pango_glyph_string_index_to_x
We should use hb-ot-layout-get-ligature-carets to get information from the font, if we can.
https://harfbuzz.github.io/harfbuzz-hb-ot-layout.html#hb-ot-layout-get-ligature-carets
We should use hb-ot-layout-get-ligature-carets to get information from the font, if we can.
https://harfbuzz.github.io/harfbuzz-hb-ot-layout.html#hb-ot-layout-get-ligature-carets