src/vs/editor/common/model/textModel.ts/TextModel/detectIndentation
class TextModel:	public detectIndentation(defaultInsertSpaces: boolean, defaultTabSize: number): void {
		this._assertNotDisposed();
		const guessedIndentation = guessIndentation(this._buffer, defaultTabSize, defaultInsertSpaces);
		this.updateOptions({
			insertSpaces: guessedIndentation.insertSpaces,
			tabSize: guessedIndentation.tabSize,
			indentSize: guessedIndentation.tabSize, // TODO@Alex: guess indentSize independent of tabSize
		});
	}