fix: improve accessibility in editor window

[Dsaquel]

This change will bring back textarea instead of an div as the editor container.

I have vimium as extension that listen on keyboard inputs, if the active element is not an inputable context it will triggers keyboard shortcut instead of plain text. Overall speaking, i think textarea will be the best for accessibility than a div.

Some references https://github.com/microsoft/monaco-editor/issues/5059, https://github.com/microsoft/vscode/pull/227608.