fixup! vfs: integrate with CJS and ESM module loaders

Restore the "DO NOT depend on the patchability" warnings in esm/load.js
and esm/resolve.js that were dropped along with the fs imports. The
warning still applies; it now also points at node:vfs as one of the
formal hook mechanisms callers should reach for instead.

Addresses review feedback from @jsumners-nr in
#63653

Author: mcollina

lib/internal/modules/esm/load.js

@@ -34,6 +34,12 @@ function getSourceSync(url, context) {
   const responseURL = href;
   let source;
   if (protocol === 'file:') {
+    // If you are reading this code to figure out how to patch Node.js module
+    // loading behavior - DO NOT depend on the patchability in new code: Node.js
+    // internals may stop going through the JavaScript fs module entirely.
+    // Prefer module.registerHooks(), node:vfs, or other more formal fs hooks
+    // released in the future. loaderReadFile is the toggleable hook used by
+    // node:vfs and is not part of the public API.
     source = loaderReadFile(url);
   } else if (protocol === 'data:') {
     const result = dataURLProcessor(url);

lib/internal/modules/esm/resolve.js

@@ -267,6 +267,12 @@ function finalizeResolution(resolved, base, preserveSymlinks) {
   }
 
   if (!preserveSymlinks) {
+    // If you are reading this code to figure out how to patch Node.js module
+    // loading behavior - DO NOT depend on the patchability in new code: Node.js
+    // internals may stop going through the JavaScript fs module entirely.
+    // Prefer module.registerHooks(), node:vfs, or other more formal fs hooks
+    // released in the future. toRealPath is the toggleable hook used by
+    // node:vfs and is not part of the public API.
     const real = toRealPath(path);
     const { search, hash } = resolved;
     resolved =