Enable use of <>-fragment (update dependencies).

Update style of solution-AND-usermarked fields.

src/ValidatingInputNumberField.js

@@ -24,14 +24,8 @@ export default function ValidatingInputNumberField({
         }
         onChange(validation.value);
     };
-    let errorComponent;
-    if (!!error) {
-        errorComponent = <span>{error}</span>;
-    } else {
-        errorComponent = <span/>;
-    }
     return (
-        <span>
+        <>
             <label htmlFor={id}>{label}: </label>
             <input id={id}
                    type={"number"}
@@ -41,7 +35,7 @@ export default function ValidatingInputNumberField({
                    max={constraints.max || null}
                    disabled={disabled}
             />
-            {errorComponent}
-        </span>
+            {!!error && <span>{error}</span>}
+        </>
     );
 }