Fix selection bug in handleMoveLines on macOS by using invokeLater()

Previously, moving lines down on macOS caused incorrect selection, moving
the cursor to the end of the enclosing braces instead of properly selecting the moved line. This issue did not occur on Windows.

The fix ensures that selection updates happen inside Swing's event
dispatch thread by wrapping the selection logic in SwingUtilities.invokeLater().
This guarantees proper selection behavior across all platforms.

Additionally, updated the JavaDoc for the method to reflect the fix and clarify
the behavior of the selection update.

Tested on Windows and macOS.

Author: yehiarasheed

app/src/processing/app/ui/Editor.java

@@ -1936,6 +1936,8 @@ public void handleIndentOutdent(boolean indent) {
    * <p>If {@code moveUp} is true, the selected lines are moved up. If false, they move down.</p>
    * <p>This method ensures proper selection updates and handles edge cases like moving
    * the first or last line.</p>
+   * <p>This operation is undo/redoable, allowing the user to revert the action using
+   * {@code Ctrl/Cmd + Z} (Undo) and redo with {@code Ctrl/Cmd + Y} (Redo).</p>
    *
    * @param moveUp {@code true} to move the selection up, {@code false} to move it down.
    */
@@ -2005,7 +2007,7 @@ public void handleMoveLines(boolean moveUp) {
               : textarea.getLineStopOffset(stopLine); // Prevent out-of-bounds
     }
 
-    textarea.select(newSelectionStart, newSelectionEnd);
+    SwingUtilities.invokeLater(() -> textarea.select(newSelectionStart, newSelectionEnd));
     stopCompoundEdit();
   }