bug#55370: [PATCH] Add support for the Syloti Nagri script

[Eli Zaretskii <eliz@gnu.org>]

> From: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
> Date: Sun, 15 May 2022 05:17:07 +0530
> Cc: 55370@debbugs.gnu.org
> 
> I have updated the patch.
> 
> 1. Wherever the nasal signs are not in range, I have not included them in a composition rule if they appear
> alone with a character and left them up to composite.el.
> For eg in Kaithi
> 
> - ;; Nasal vowels
> - (concat independent-vowel nasal "?")
> + ;; Vowel based syllables
> + (concat independent-vowel nukta "?" virama "?" vowel "?")
> 
> 2. I have also written composition rules for independent vowels with nukta, virama, vowel signs etc, so that
> Emacs does not hang when they are typed together.
> 
> Please review the patch.

Thanks.  I installed this, but please review the composition rules,
because in the Syloti Nagri greeting some characters whose Unicode
general-category property is Mn, which means they are combining
characters, don't compose.  That doesn't feel right to me, but I don't
read this script.  Just go through the greeting with C-f and type
"C-u C-x =" at every cursor position: you will see some of the
characters are shown as "combining", but they don't compose with
surrounding characters.

I didn't look at the other scripts you added, but maybe they, too,
have similar problems.