Simpler JSON generation

[P1xel1ze]

I ws trying to fix a bug where the language ID for JSONL didn't work properly but I had to look through so many confusing files just to edit it since the file (material-icons.json) is generated and not manually written so I still don't know if my fix even worked until the PR commit is in a release so I was just thinking that maybe it would make more sense if the JSON file was just edited by hand or you have one script that combines different JSON files so that you can easily edit, say, languageIDs.json and fileExtensions.json seperatly but you don't have to jump through a ton of TypeScript files