src/vs/workbench/contrib/scm/browser/dirtydiffDecorator.ts/DirtyDiffController/next
class DirtyDiffController:	next(lineNumber?: number): void {
		if (!this.assertWidget()) {
			return;
		}
		if (!this.widget || !this.model) {
			return;
		}

		if (this.editor.hasModel() && (typeof lineNumber === 'number' || this.currentIndex === -1)) {
			this.currentIndex = this.model.findNextClosestChange(typeof lineNumber === 'number' ? lineNumber : this.editor.getPosition().lineNumber);
		} else {
			this.currentIndex = rot(this.currentIndex + 1, this.model.changes.length);
		}

		this.widget.showChange(this.currentIndex);
	}