patch 8.2.0289: Vim9: :echo did not clear the rest of the line

Problem:    Vim9: :echo did not clear the rest of the line.
Solution:   Call msg_clr_eos(). (Ken Takata, closes #5668)
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 7be8cdb..3bbf94f 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -527,6 +527,8 @@
 							   &atstart, &needclr);
 			clear_tv(tv);
 		    }
+		    if (needclr)
+			msg_clr_eos();
 		    ectx.ec_stack.ga_len -= count;
 		}
 		break;