This is visible in VSE text strip "box" and "outline" options at least.
For some fonts (mostly script/cursive type) BLF_boundbox function
was calculating horizontal bounds purely from pen position and
advance to the next character position. But the actual glyph can extend
beyond the advance distance.
Curiously, blf_font_boundbox_foreach_glyph (used by
blf_str_offset_from_cursor_position and blf_str_offset_to_glyph_bounds)
was already doing the correct thing and taking glyph horizontal bounds
into account.
