Layers: art moved into a hidden or locked layer, or hidden by a data set, is deselected

These commands moved selected objects into a hidden or locked layer,
or hid them, and left them selected, with the key object still set
when it was one of them:

- a row dragged into a hidden layer or group (layer.move);
- node.move into a hidden or locked layer or group;
- Merge Selected into a hidden or locked layer;
- Flatten Artwork into a locked layer;
- Collect in New Layer, when the topmost row it collects is in a
  hidden or locked layer;
- applying a data set that hides bound objects (dataset.select,
  dataset.next, dataset.prev).

They now call Selection::deselect_uneditable after the change, as
layer.setProps, layer.hideOthers and layer.lockOthers do. Every
selected object left hidden or locked is deselected, and the key
object is cleared when it is one of them. Undo restores the objects
and selects them again with the key object. A row drag into a hidden
layer and node.move into a hidden or locked layer still succeed. The
params text of layer.move, node.move, layer.merge, layer.flatten,
layer.collectInNew and dataset.select describes the deselection.

The Layers panel section of docs/mcp.md said that node.move has the
same rules as layer.move; it now says that node.move also moves a row
into a locked layer or group, which layer.move refuses.

Docs: docs/mcp.md, docs/target-app-parity.md.

docs/mcp.md

@@ -752,6 +752,11 @@ that were already hidden or locked. The key object is cleared when it is one of
 them again with the key object. When the call changes nothing, it records no undo step and still deselects them.
 Other `object.setProps` calls leave the selection unchanged.
 
+`layer.move`, `node.move`, `layer.merge`, `layer.flatten`, `layer.collectInNew`, `dataset.select`, `dataset.next`
+and `dataset.prev` also deselect every selected object that is hidden or locked after the call, such as objects
+moved into a hidden or locked layer or group, or objects that a data set hides. The key object is cleared when it
+is one of them, and `edit.undo` selects them again with the key object.
+
 These Select menu commands select only the objects that `select.all` selects and the objects inside them: every
 `select.same.*` and `select.object.*` command except `select.object.slices`, `select.nextAbove`, `select.nextBelow`
 and `select.recall`. They leave out hidden and locked objects with the objects inside them, the objects on hidden,
@@ -1142,7 +1147,7 @@ and `layerRows`, the rows highlighted in the panel.
   only in layers or at the top level and objects in layers and groups (an object placed beside a top-level layer goes
   inside it); a row never goes into itself or a row inside it, and a locked layer or group takes nothing. Dragging the
   selected-art square is `layer.move` with the selected objects. `node.move {id, parent?, index}` is the low-level
-  form with the same rules.
+  form with the same nesting rules; unlike `layer.move`, it also moves a row into a locked layer or group.
 - **Buttons**: `layer.new {name?, top?, …options}` (above the current layer at its level; `top` with Ctrl/Cmd),
   `layer.newSublayer {parent?, name?, …options}` (on top of the parent's contents), `layer.delete {ids?}` (rows with
   what they hold; the last layer stays), `layer.locate {id?}` (highlights the selected object's row; the panel opens