Ctrl+D multiselection support for notebooks (microsoft#226206)

* wip

* onWillType relays for cursorControllers

* esc multi select mode action + context key

* composition wip

* Construct editor options on the fly.

* Keep cursor model in contrib.

* Avoid exposing getCellIndexByHandle

* constructCoordinatesConverter

* cursor decoration improvement, lazy decorations, when clauses

* setting for when clause + cursor exits

* clean decorations + cursor exit selecting state

---------

Co-authored-by: Peng Lyu <[email protected]>

Author: Yoyokrazy

src/vs/editor/common/model/textModel.ts

@@ -1989,7 +1989,7 @@ export class TextModel extends Disposable implements model.ITextModel, IDecorati
 	}
 }
 
-function indentOfLine(line: string): number {
+export function indentOfLine(line: string): number {
 	let indent = 0;
 	for (const c of line) {
 		if (c === ' ' || c === '\t') {