fixed the order for word insert

app.py

@@ -29,7 +29,7 @@ def diff_strings(a, b):
                 replacement = ""
         elif line.startswith("+ "):
             if len(replacement) == 0:
-                result.append(("", line[2:], "#dfd"))
+                result.append((line[2:], "", "#dfd"))
             else:
                 result.append(" ")
                 result.append((line[2:], replacement, "#ddf"))