EQL Mode for Codemirror 6

[wilkerlucio]

The current Pathom Mode is made for Codemirror 5.

Recently NextJournal made a better Clojure mode, targeting CodeMirror 6.

CodeMirror 6 is a rewrite of the CodeMirror code editor. It greatly improves the library's accessibility and touchscreen support, provides better content analysis and a modern programming interface. The new system matches the existing code in features and performance. It is not API-compatible with the old code.

I believe the way forward is to write a new mode, for Codemirror 6, we can call it EQL Mode.

One note: Codemirror 6 is already included in Pathom Viz, its used on the Clojure read-only parts of the UI, this way users can take leverage of the folding feature present there (which is a big deal to visualize large data structures).