Fixing NumberUtils JAVADoc comments for max methods

Fixing NumberUtils JAVADoc  comments of the following methods:
* `public static long max(final long[] array)`
* `public static long max(final int[] array)`
* `public static long max(final short[] array)`
* `public static long max(final byte[] array)`
* `public static long max(final double[] array)`
* `public static long max(final float[] array)`

all of these methos above had the wrong return description
```
 @return the minimum value in the array
// so i fixed to 
 @return the maximum value in the array
```
Jira ticket https://issues.apache.org/jira/browse/LANG-1007