TextYankPost: spurious/too-early dispatch during delete #10392

Problem: delete-with-register dispatches TextYankPost before updating yank registers
Solution: Add flag to op_yank().

Fixes #10225

src/nvim/ex_docmd.c

@@ -7520,7 +7520,7 @@ static void ex_operators(exarg_T *eap)
 
   case CMD_yank:
     oa.op_type = OP_YANK;
-    (void)op_yank(&oa, true);
+    (void)op_yank(&oa, true, false);
     break;
 
   default:          /* CMD_rshift or CMD_lshift */