* Allow extensions to disable built-in markdown preview button
Adds a flag for the "Open Preview to the Side" button displayed for markdown files. This makes it possible for extensions to hide this button when desired by setting the flag to true. For example, extensions can now use the following line to disable the preview button:
```js
vscode.commands.executeCommand("setContext", "hasCustomMarkdownView", true);
```
* update keyword for disabling default markdown preview
* 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>
