bug#58098: Improve composition rules for Gumrukhi

[Eli Zaretskii <eliz@gnu.org>]

> From: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
> Date: Tue, 27 Sep 2022 19:22:09 +0530
> Cc: 58098@debbugs.gnu.org
> 
>  I don't understand this part: why should we require #x1FA67?  Did you
>  perhaps mean this:
> 
>        (chess-symbol . [#x1FA00 #x1FA67])
> 
> Isn't the script-representative-chars used to improve font selection by requesting more characters?
> So does the specific character requested have any effect? because I chose it randomly.

The form

       (chess-symbol #x1FA00 #x1FA67)

requires that _both_ #x1FA00 and #x1FA67 be supported by a font, for
it to be eligible to display chess-symbols.  By contrast, the form

       (chess-symbol . [#x1FA00 #x1FA67])

requires that _either_ of the two characters is supported.  So my
question is: do we really want _both_ of the characters supported by a
font, and if not, do we really want Emacs to reject such a font?

Did you look at what #x1FA67 looks like?  It is not a "traditional"
chess symbol.  And neither are the characters that are its neighbors.

>  We already have the setup for chess-symbol, below this line where you
>  are making changes.  Is it not enough for some reason?
> 
> Prior to this patch the chess symbol block was not rendered on my machine despite having its font (Noto
> Sans Symbols2) 

You don't have Symbola installed?