patch 8.2.1281: the "trailing characters" error can be hard to understand

Problem:    The "trailing characters" error can be hard to understand.
Solution:   Add the trailing characters to the message.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index c07b1ab..a631fd9 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2141,7 +2141,7 @@
 	rettv->vval.v_number = 0;
     }
     else if (*s != NUL)
-	emsg(_(e_trailing));
+	semsg(_(e_trailing_arg), s);
 }
 
 /*
@@ -5113,7 +5113,7 @@
     if (end != NULL && lv.ll_name != NULL)
     {
 	if (*end != NUL)
-	    emsg(_(e_trailing));
+	    semsg(_(e_trailing_arg), end);
 	else
 	{
 	    if (lv.ll_tv == NULL)