chore: Move editor into codebase (#2930)

shared/editor/queries/getRowIndex.ts

@@ -0,0 +1,9 @@
+import { CellSelection } from "prosemirror-tables";
+
+export default function getRowIndex(selection: CellSelection) {
+  const isRowSelection = selection.isRowSelection && selection.isRowSelection();
+  if (!isRowSelection) return undefined;
+
+  const path = (selection.$from as any).path;
+  return path[path.length - 8];
+}