[guide] clean up confusing example from bad rebase

 ... from
airbnb@820745d#diff-04c6e90faac2675aa89e2176d2eec7d8R963-R965
/ airbnb#1863.

Fixes airbnb#2071.

Author: ljharb

README.md

@@ -960,9 +960,6 @@ Other Style Guides
       `A string containing the ${nextNumber}.`;
     });
 
-    // bad
-    [1, 2, 3].map((number) => `A string containing the ${number}.`);
-
     // good
     [1, 2, 3].map((number) => `A string containing the ${number + 1}.`);