src/vs/workbench/contrib/terminal/browser/xterm/markNavigationAddon.ts/MarkNavigationAddon/_createMarkerForOffset
class MarkNavigationAddon:	private _createMarkerForOffset(marker: IMarker, offset: number): IMarker {
		if (offset === 0) {
			return marker;
		} else {
			const offsetMarker = this._terminal?.registerMarker(-this._terminal.buffer.active.cursorY + marker.line - this._terminal.buffer.active.baseY + offset);
			if (offsetMarker) {
				return offsetMarker;
			} else {
				throw new Error(`Could not register marker with offset ${marker.line}, ${offset}`);
			}
		}
	}