A tab with Tree-sitter code editor

[arnobl]

Add a new tab that will contain a novel code editor.
This differs of the text area. The idea here is to have a text area that looks like a code editor (like this one: https://tree-sitter.github.io/tree-sitter/playground).
To do so, we will use tree-sitter:

• have an editable div (not a text area, <div contenteditable="true">)
• Use the Java tree-sitter (https://tree-sitter.github.io//tree-sitter-java.wasm) parser in the app: https://github.com/tree-sitter/tree-sitter/blob/master/lib/binding_web/README.md#setup
• Investigate whether tree-sitter can provide the changed elements of a modified AST (https://github.com/tree-sitter/tree-sitter/blob/master/lib/binding_web/README.md#editing)
• Instead of having a linear undo history, investigate an undo history that undoes/redoes block of changed elements. For example if I write int i = 0;tree-sitter with produce the following AST. This will correspond to a main command composed of nested ones: type that contains declarator that contains name and value. So ctrl-Z will undo value first, then name, etc.

      field_declaration [1, 1] - [1, 13]
        type: integral_type [1, 1] - [1, 4]
        declarator: variable_declarator [1, 5] - [1, 12]
          name: identifier [1, 5] - [1, 8]
          value: decimal_integer_literal [1, 11] - [1, 12]