Added dictionary key mustfail test

test/scripts/mustfail/declare-types-dictionary-key.toy

@@ -0,0 +1,7 @@
+{
+	var t = astype [string:int];
+	var dict: t = ["one": 1, "two": 2, 3:4];
+}
+
+
+print "All good";

test/test_mustfail.c

@@ -128,7 +128,8 @@ int main() {
 		//run each file in tests/scripts/
 		char* filenames[] = {
 			"declare-types-array.toy",
-			"declare-types-dictionary.toy",
+			"declare-types-dictionary-key.toy",
+			"declare-types-dictionary-value.toy",
 			NULL
 		};