[gimp/gimp-2-10] Update NEWS some more

[Alexandre Prokoudine <aprokoudine src gnome org>]

commit 6d3c742b36aafbedd42a8e38d0af4609b71dac10
Author: Alexandre Prokoudine <alexandre prokoudine gmail com>
Date:   Fri Jan 10 11:51:30 2020 +0300

    Update NEWS some more

 NEWS | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)
---
diff --git a/NEWS b/NEWS
index 1fd01e702d..ea13fdc042 100644
--- a/NEWS
+++ b/NEWS
@@ -37,11 +37,22 @@ UI:
     and modifier used:
 
     - left-click is used for absolute adjustment,
-    - shift + left-click + drag changes value in small increments,
-    - ctrl + left-click + drag changes value in large increments,
+    - Shift + left-click + drag changes value in small increments,
+    - Ctrl + left-click + drag changes value in large increments,
     - middle-click enables numeric input mode;
     - right-click enables numeric input mode and select the value.
 
+  - Consolidate UI for merging down and anchoring layers:
+    As they are both mutually exclusive and serve an almost identical
+    purpose, the "Merge down" and "Anchor Layer" are given mutually
+    exclusive visibility in menus, and the anchor button is replaced
+    with a merge down button in the Layers dockable whenever there is
+    no active floating selection. Modifier keys are available:
+
+    - Shift: merge layer group
+    - Ctrl: merge visible layers
+    - Ctrl + Shift: merge visible layers from last used values
+
 Plugins:
 
   - In plug_in_compat.pdb, when wrapping an op node inside a graph,