NEWS: Moved "Integer#[] with range" to "Core classes updates"

NEWS

@@ -42,13 +42,6 @@ sufficient information, see the ChangeLog file or Redmine
 * Setting <code>$,</code> to non-nil value is warned now.  Use of it in
   Array#join is warned too.
 
-* <code>Integer#[]</code> now supports range operation.  [Feature #8842]
-
-     0b01001101[2, 4]  #=> 0b0011
-     0b01001100[2..5]  #=> 0b0011
-     0b01001100[2...6] #=> 0b0011
-         ^^^^
-
 === Core classes updates (outstanding ones only)
 
 Enumerable::
@@ -65,6 +58,17 @@ Enumerator::
       can be directly passed to another method as a block
       argument.  [Feature #15618]
 
+Integer::
+
+  Modified method::
+
+    * Integer#[] now supports range operation.  [Feature #8842]
+
+         0b01001101[2, 4]  #=> 0b0011
+         0b01001100[2..5]  #=> 0b0011
+         0b01001100[2...6] #=> 0b0011
+             ^^^^
+
 Regexp/String::
 
     * Update Unicode version and Emoji version from 11.0.0 to