bug#57072: [BUG] update-glyphless-char-display and variation selectors

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  57072@debbugs.gnu.org
> Date: Tue, 16 Aug 2022 16:48:07 +0200
> 
> --- a/admin/unidata/blocks.awk
> +++ b/admin/unidata/blocks.awk
> @@ -224,9 +224,11 @@ FILENAME ~ "emoji-data.txt" && /^[0-9A-F].*; 
> Emoji_Presentation / {
>  
>  END {
>      idx = 0
> -    # ## These are here so that font_range can choose Emoji presentation
> -    # ## for the preceding codepoint when it encounters a VS
> -    override_start[idx] = "FE00"
> +    ## This is here so that font_range can choose Emoji presentation
> +    ## for the preceding codepoint when it encounters a VS-16 (U+FE0F).
> +    ## It originally covered the whole FE00-FE0F range, but that
> +    ## turned out to be a mistake.
> +    override_start[idx] = "FE0F"
>      override_end[idx] = "FE0F"
>  
>      for (k in override_start)
> 

That LGTM, thanks.  But please mention in the comment the stuff in
composite.el which handles the other variation selectors, so that
these different places would be easier to find and inspect.