#3192 Adding docs and visual test

cypress/integration/rendering/flowchart-v2.spec.js

@@ -670,6 +670,17 @@ title: Simple flowchart
 ---
 flowchart TD
 A --> B
+`,
+      { titleTopMargin: 0 }
+    );
+  });
+  it('3192: It should be possieble to render flowcharts with invisisble edges', () => {
+    imgSnapshotTest(
+      `---
+title: Simple flowchart with invisisble edges
+---
+flowchart TD
+A ~~~ B
 `,
       { titleTopMargin: 0 }
     );