Update NEWS for v2.4.0

NEWS

@@ -2,6 +2,13 @@ News file for Stow.
 
 * Changes in version 2.4.0
 
+*** --dotfiles now works with directories
+
+    A long-standing bug preventing the --dotfiles option from working
+    correctly with directories has been fixed.
+
+    It should also works in combination with the --compat option.
+
 *** Eliminated a spurious warning on unstowing
 
     2.3.1 introduced a benign but annoying warning when unstowing
@@ -11,6 +18,14 @@ News file for Stow.
 
     This was caused by erroneous logic, and has now been fixed.
 
+*** Unstowing logic has been improved in other cases
+
+    Several other improvements have been made internally to the
+    unstowing logic.  These changes should all be either invisible
+    (except for changes to debug output) or improvements, but if you
+    encounter any unexpected behaviour, please report it as directed
+    in the manual.
+
 *** Improved debug output
 
     Extra output resulting from use of the -v / --verbose flag