IT testing for multiple characters (ִרֹ) that occupy 1 display string.

[Keith David Bershatsky]

I am working on feature requests #17684 (crosshairs) and #22873 (multiple fake 
cursors).

When using move_it_in_display_line_to, ִרֹ is treated as one display string; 
however, it is 3 different characters occupying 3 HPOS.  it->c only reports 
1460.

I initially guessed that this was a composition situation, however, it.what 
returns a 0, which is the same as any other regular character.

Q:  How do we test for this situation, so that we know all of the different 
characters and each of their individual pixel widths?

Thanks,

Keith