* Better notebook markup renderer api
For #121256
- Use js modules for notebook output renderers
- Rename apis from `markdown` to `markup`
- Use imports and exports for apis instead of globals for apis
- Use esbuild instead of webpack so we can emit js modules
- Clearly split top level markup renderes from renderers that extend other renderers
* Use constant instead of comment for replacement
* Use shared webpack version instead of installing locally for simple-browser
* Use npm for building markdown preview
* render markdown in webview.
* update markdown preview height and offset
* Add basic custom notebook renderer point
* update css
* style update.
* update markdown header padding left
* Add example of loading katex to extend the markdown-it renderer
* Rename global to make clear it only applies to markdown-in
* hide/remove markdown preview
* Add wait for initial markdown preview rendering before showing notebook
* Add double click to switch to editing mode
* Fix markdown cells not getting updated after editing
* style polish
* notebook.experimental.useMarkdownRenderer
* switch render strategy.
* Adding very intial drag drop support for notebook markdown cells
* Implement drag/drop stubs for test classes
* Revert unrelated file changes
* Move markdown notebook math to own extension
* Add missing imports
Co-authored-by: rebornix <penn.lv@gmail.com>
Matt Bierner
