feat(CSS): add space to computations using join(' ')

Author: josueJURE

index.js

@@ -222,7 +222,7 @@ function userClicksOnEqualButton(button) {
           console.log(entry);
           history.push(entry);
           console.log(history);
-          historyElement.innerHTML += `<li>${entry.join("")}</li>`
+          historyElement.innerHTML += `<li>${entry.join(" ")}</li>`
         });
 
       }