Update codemirror to version 6

[kjhollen]

How would this new feature help increase access to the p5.js Editor?

CodeMirror v6 has accessibility support! I'm not sure what else is required to upgrade and activate the accessibility features, but it seems this is built in to the library now.

Feature enhancement details:

According the current package.json file, we're still using CodeMirror 5, which is not compatible with screenreaders. Upgrading to 6.0 or later should fix this.

[catarak]

I actually created a prototype that used CodeMirror 6 a year and a half ago (see the branch feature/codemirror-6-prototype). Probably a good starting point to get it to work with everything that was implemented in CM5!

[lindapaiste]

I’ve been working on this and making a lot of progress!

I set it up so that the editor only knows about the currently-selected file. When the file is changed then it will change the extensions for language/linting/etc. (which involves using CodeMirror “Compartments” instead of React state updates).

I’m hoping to have something PR-worthy soon but there are still some features that I need to implement. For example I’ve got the search box mostly functional but they don’t have any method that gives you the total result count.