[TextServer] Add extra fallback step, to lookup for individual characters.

[bruvzg]

Fixes godotengine/godot-proposals#9043

[dhoverml]

I cherry-picked this to master (4e990cd) and I no longer see tofu glyphs when I apply accents to non-Arabic characters.

However, this may be a separate bug, but I see that the cursor switches to the other side of the character when I'm typing the accents, but it fixes itself once I start typing Arabic characters again.

I typed ض (q on my keyboard), #, then added an accent (Q on my keyboard) into a LineEdit node. The cursor remains on the left side until I type the accent mark (with Q), where it then teleports to the right side of the #

The cursor remains on the left side when I repeat the same steps in my browser's URL bar (I added a few extra accents so you can see them)

Also, in Godot, the non-Arabic glyph that I'm applying an accent to moves to the far right side of the current list of non-Arabic glyphs.
Alternate between typing #, @, $, and an accent.

Ok:
Ok:
Bad:
Ok:
Bad:

Same sequence in a browser produces different results:

[bruvzg]

However, this may be a separate bug, but I see that the cursor switches to the other side of the character when I'm typing the accents, but it fixes itself once I start typing Arabic characters again.

Pushed update to fix the direction, it should work correctly now.

[dhoverml]

Wow that was fast!
I tested the latest patch, and it looks great!

The only problem I see is that it's switching the original glyph's font when it applies the accent:

This 3 is AlbertSans-Regular.ttf

When I apply an accent, the 3 is reshaped with NotoSansArabic-Regular.ttf

The workaround is to put the Arabic font first in the list of fallbacks.
Also, I'm not too worried about this since I see some applications (like Github's text-input field) do the same. Though some applications don't (like the Browser URL bar).

Anyway, this is great, thanks!

[akien-mga]

Thanks!