Add vendoring notice to the two vendored libs

lib/gluejar.ts

@@ -1,3 +1,5 @@
+// Vendored from @charliewilco/gluejar on npm (not marked compatible with React 18)
+
 import { useEffect, useCallback, useReducer } from "react";
 
 /* <PasteContainer

lib/qr.ts

@@ -1,3 +1,5 @@
+// Vendored from qrcode-decoder on npm (was giving me Webpack issues)
+
 import { Options } from 'jsqr';
 import jsQR from 'jsqr';