generate-css: Add codepoint to glyphnames.json

[why]
Just having the characters themselves as data for the name is convenient
in some cases; but sometimes the codepoint is also nice. And it
certainly improves the human interaction / check of the file.

[how]
Include the character and the codepoint in the glyph-name data. This is
a breaking change. But given that the json file is rather new I believe
we can get away with it.

Sorry for the inconvenience for all the early adaptors that already use
the old/previous format. But now we are more future proof and can add
even more data without breaking old json code.

Related:
#1140
kovidgoyal/kitty#2972
chrisbra/unicode.vim#39
#448
nvim-tree/nvim-web-devicons#192

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

Author: Finii

bin/scripts/generate-css.sh

@@ -108,7 +108,7 @@ for var in "${!i@}"; do
 
   # generate json entry
   {
-    printf ",\"%s\":\"%s\"" "$glyph_name" "$glyph_char"
+    printf ",\"%s\":{\"char\":\"%s\",\"code\":\"%s\"}" "$glyph_name" "$glyph_char" "$glyph_code"
   } >> "$output_json_file"
 
 done