patch 8.1.1692: using *{} for literal dict is not backwards compatible

Problem:    Using *{} for literal dict is not backwards compatible. (Yasuhiro
            Matsumoto)
Solution:   Use ~{} instead.
diff --git a/src/eval.c b/src/eval.c
index ae89f7e..1d290bc 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -4266,7 +4266,7 @@
     for (;;)
     {
 	op = **arg;
-	if ((op != '*' || (*arg)[1] == '{') && op != '/' && op != '%')
+	if (op != '*' && op != '/' && op != '%')
 	    break;
 
 	if (evaluate)
@@ -4392,7 +4392,7 @@
  *  (expression)	nested expression
  *  [expr, expr]	List
  *  {key: val, key: val}   Dictionary
- *  *{key: val, key: val}  Dictionary with literal keys
+ *  ~{key: val, key: val}  Dictionary with literal keys
  *
  *  Also handle:
  *  ! in front		logical NOT
@@ -4577,9 +4577,9 @@
 		break;
 
     /*
-     * Dictionary: *{key: val, key: val}
+     * Dictionary: ~{key: val, key: val}
      */
-    case '*':	if ((*arg)[1] == '{')
+    case '~':	if ((*arg)[1] == '{')
 		{
 		    ++*arg;
 		    ret = dict_get_tv(arg, rettv, evaluate, TRUE);