[Tu2525]

Summary

• place right-to-left DirectWrite glyph runs at the baseline origin DirectWrite reports, so Arabic and Hebrew read in order instead of mirrored
• wrap right-to-left text by how much of the line each glyph covers, and lay out each wrapped line so it still reads from the right
• paint underlines, strikethroughs and backgrounds across the glyphs they cover in right-to-left text
• place the caret, and find the character under a click, on the side each character is read from
• treat Hebrew and Arabic letters as word characters, so wrapping breaks between words rather than inside them
• keep left-to-right text on the existing code paths