NEWS: Separate removed constants section

NEWS.md

@@ -49,7 +49,7 @@ Note: We're only listing outstanding class updates.
 
 Note: Excluding feature bug fixes.
 
-### Removed methods
+### Removed constants
 
 The following deprecated constant is removed.
 
@@ -57,6 +57,8 @@ The following deprecated constant is removed.
 * `Struct::Group`
 * `Struct::Passwd`
 
+### Removed methods
+
 The following deprecated methods are removed.
 
 * `Dir.exists?` [[Feature #17391]]