Enable insert in the start of table cell (#1880)

* Enable insert in the beginning of table

* Faster Return

examples/tables/index.js

@@ -89,8 +89,12 @@ class Tables extends React.Component {
       const prevBlock = document.getClosestBlock(previous.key)
 
       if (prevBlock.type == 'table-cell') {
-        event.preventDefault()
-        return true
+        if (['Backspace', 'Delete', 'Enter'].includes(event.key)) {
+          event.preventDefault()
+          return true
+        } else {
+          return
+        }
       }
     }