demo/testing: add function test for tabulature (guitar tab)

demo/index.js

@@ -36,6 +36,7 @@ import { OpenSheetMusicDisplay } from '../src/OpenSheetMusicDisplay/OpenSheetMus
             "OSMD Function Test - Selecting Measures To Draw": "OSMD_function_test_measuresToDraw_Beethoven_AnDieFerneGeliebte.xml",
             "OSMD Function Test - Notehead Shapes": "OSMD_function_test_noteheadShapes.musicxml",
             "OSMD Function Test - Ornaments": "OSMD_function_test_Ornaments.xml",
+            "OSMD Function Test - Tabulature": "OSMD_Function_Test_Tabulature_hayden_study_1.mxl",
             "OSMD Function Test - Tremolo": "OSMD_Function_Test_Tremolo_2bars.musicxml",
             "Schubert, F. - An Die Musik": "Schubert_An_die_Musik.xml",
             "Actor, L. - Prelude (Large Sample, loading time)": "ActorPreludeSample.xml",