Add additional replace rules for node:* modules

In that particular issue the compiled nuxt files end up importing the
http module as node:http rather than http only. This bypasses unit's
custom loader implementation which only check for the http or unit-http
modules, and their websocket counterparts.

This changeset adds replace sources for both the node:http and
node:websocket import signatures.

Closes: https://github.com/nginx/unit/issues/1013
Reviewed-by: Andrew Clayton <a.clayton@nginx.com>

src/nodejs/unit-http/loader.js

@@ -11,10 +11,12 @@ if (module.parent && module.parent.id === "internal/preload") {
         Module.prototype.require = function (id) {
             switch(id) {
                 case "http":
+                case "node:http":
                 case "unit-http":
                     return http
 
                 case "websocket":
+                case "node:websocket":
                 case "unit-http/websocket":
                     return websocket
             }

src/nodejs/unit-http/loader.mjs

@@ -2,6 +2,7 @@
 export async function resolve(specifier, context, defaultResolver) {
     switch (specifier) {
         case "websocket":
+        case "node:websocket":
             return {
                 url: new URL("./websocket.js", import.meta.url).href,
                 format: "commonjs",
@@ -9,6 +10,7 @@ export async function resolve(specifier, context, defaultResolver) {
             }
 
         case "http":
+        case "node:http":
             return {
                 url: new URL("./http.js", import.meta.url).href,
                 format: "commonjs",