patch 7.4.1160

Problem:    No error for jsondecode('"').
Solution:   Give an error message for missing double quote.

Author: brammool

src/json.c

@@ -406,6 +406,7 @@ json_decode_string(js_read_T *reader, typval_T *res)
     }
     else
     {
+	EMSG(_(e_invarg));
 	res->v_type = VAR_SPECIAL;
 	res->vval.v_number = VVAL_NONE;
     }

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1160,
 /**/
     1159,
 /**/