patch 8.1.0563: setting v:errors to a string give confusing error

Problem:    Setting v:errors to a string give confusing error. (Christian
            Brabandt)
Solution:   Change internal error into normal error message.

Author: brammool

src/eval.c

@@ -7568,7 +7568,7 @@ set_var(
 		return;
 	    }
 	    else if (v->di_tv.v_type != tv->v_type)
-		internal_error("set_var()");
+		EMSG2(_("E963: setting %s to value with wrong type"), name);
 	}
 
 	clear_tv(&v->di_tv);

src/version.c

@@ -792,6 +792,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    563,
 /**/
     562,
 /**/