Update spec.html

Author: LingDong-

static/spec.html

@@ -31,7 +31,7 @@
 
 </style>
 <script>
-var bnf_path = "https://raw.githubusercontent.com/LingDong-/wenyan-lang/new_compiler/antlr/cpp/wenyan.g4"
+var bnf_path = "https://raw.githubusercontent.com/LingDong-/wenyan-lang/master/documentation/wenyan.g4"
 
 function rich(txt){
   function anchor(t,other){
@@ -62,4 +62,4 @@
   .then((txt) => {
     document.body.innerHTML = "<i style='font-size:18px;font-family:serif'>Wenyan Language Specification</i><br><br>"+rich(txt);
   });
-</script>
+</script>