chore: update new ref sugar warning link

Author: yyx990803

packages/compiler-sfc/src/compileScript.ts

@@ -548,7 +548,10 @@ export function compileScript(
         decl.init
       )
     } else {
-      warnExperimental(`ref sugar`, 0 /* TODO */)
+      warnExperimental(
+        `ref sugar`,
+        `https://github.com/vuejs/rfcs/discussions/369`
+      )
     }
 
     const callee = (decl.init.callee as Identifier).name

packages/compiler-sfc/src/warn.ts

@@ -15,14 +15,14 @@ export function warn(msg: string) {
   )
 }
 
-export function warnExperimental(feature: string, rfcId: number) {
+export function warnExperimental(feature: string, url: string) {
   // eslint-disable-next-line
   if (typeof window !== 'undefined') {
     return
   }
   warnOnce(
     `${feature} is still an experimental proposal.\n` +
-      `Follow its status at https://github.com/vuejs/rfcs/pull/${rfcId}.`
+      `Follow its status at ${url}.`
   )
   warnOnce(
     `When using experimental features,\n` +