Add spacing for multiple tables scenario

When there are multiple tables back to back the
edges are butted up against each other. We don't want table elements right up against other elements so we need to add some margin.

Author: dhruvisompura

src/vs/workbench/contrib/positronNotebook/browser/notebookCells/Markdown.css

@@ -101,6 +101,7 @@
 	table {
 		border-collapse: collapse;
 		border-spacing: 0;
+		margin-bottom: 0.7em;
 	}
 
 	table th,