Update en.json

correction in demorgan 3 and 4

src/lang/en.json

@@ -60,13 +60,13 @@
           "demorgan1": "You have applied De Morgan incorrectly, don't forget the negation signs.",
           "demorgan2": "When applying De Morgan, don't forget to remove the negation sign outside of the brackets.",
           "demorgan3": {
-            "#": "When applying De Morgan, don't forget to change the disjunction into a conjunction.",
-            "inv": "When applying De Morgan, don't forget to change the disjunction into a conjunction."
-          },
-          "demorgan4": {
             "#": "When applying De Morgan, don't forget to change the conjunction into a disjunction.",
             "inv": "When applying De Morgan, don't forget to change the conjunction into a disjunction."
           },
+          "demorgan4": {
+            "#": "When applying De Morgan, don't forget to change the disjunction into a conjunction.",
+            "inv": "When applying De Morgan, don't forget to change the disjunction into a conjunction."
+          },
           "demorgan5": "When applying De Morgan, take care where you place the brackets. You have inadvertently changed the application range of the negation.",
           "distr": {
             "#": "You have applied distribution incorrectly. Take care where you put the conjunctions and where you put the disjunctions.",