docs: add documentation about the __VUE_PROD_TRUSTED_TYPES__ flag

Author: haoqunjiang

packages/runtime-core/src/featureFlags.ts

@@ -25,6 +25,11 @@ export function initFeatureFlags() {
     getGlobalThis().__VUE_PROD_HYDRATION_MISMATCH_DETAILS__ = false
   }
 
+  if (typeof __FEATURE_PROD_TRUSTED_TYPES__ !== 'boolean') {
+    __DEV__ && needWarn.push(`__VUE_PROD_TRUSTED_TYPES__`)
+    getGlobalThis().__VUE_PROD_TRUSTED_TYPES__ = false
+  }
+
   if (__DEV__ && needWarn.length) {
     const multi = needWarn.length > 1
     console.warn(

packages/vue/README.md

@@ -49,6 +49,10 @@
   - Default: `false`
   - Enable / disable detailed warnings for hydration mismatches in production
 
+- `__VUE_PROD_TRUSTED_TYPES__`
+  - Default: `false`
+  - Enable / disable built-in Trusted Types Policy for compatibility with the [`trusted-types` CSP directive](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/trusted-types)
+
 The build will work without configuring these flags, however it is **strongly recommended** to properly configure them in order to get proper tree-shaking in the final bundle.
 
 ### For Server-Side Rendering