Ctrl-K corrected behavior on whitepsace lines

- If lines contained only whitespace, Ctrl-K was deleting all subsequent
  lines in the file.
- Now behavior matches Emacs, where whitespace only lines get deleted
  from caret forward, including newline break.

Commands/Text/DeleteToEndOfLineCommand.cs

@@ -57,6 +57,7 @@ internal override void Execute(EmacsCommandContext context)
                         {
                             // reached end of line and every character was a whitespace
                             context.EditorOperations.Delete(caretPosition, startOfNextLine - caretPosition);
+                            break;
                         }
                     }
                 }