Update and rename is_empty.ts to contains_only_empty_strings.ts

Author: Mqxx

src/array/is_empty.ts renamed to src/array/contains_only_empty_strings.ts

@@ -18,6 +18,6 @@
  * @param input The input array to check
  * @return If the array is empty
  */
-export default function isEmpty(input : string[]) : boolean {
+export default function containsOnlyEmptyStrings(input : string[]) : boolean {
   return input.join('') === '';
 }