esm: shorten ERR_UNSUPPORTED_ESM_URL_SCHEME message

I know it just got modified to include new information, but this
shortens the message a bit without (I hope) losing clarity or meaning.

PR-URL: #34836
Backport-PR-URL: #35385
Reviewed-By: Guy Bedford <[email protected]>
Reviewed-By: Denys Otrishko <[email protected]>

Author: Trott

lib/internal/errors.js

@@ -1404,8 +1404,8 @@ E('ERR_UNSUPPORTED_DIR_IMPORT', "Directory import '%s' is not supported " +
 E('ERR_UNSUPPORTED_ESM_URL_SCHEME', (url) => {
   let msg = 'Only file and data URLs are supported by the default ESM loader';
   if (isWindows && url.protocol.length === 2) {
-    msg += '. Absolute Windows paths without prefix are not valid URLs, ' +
-      "consider using 'file://' prefix";
+    msg +=
+      '. On Windows, absolute paths must be valid file:// URLs';
   }
   msg += `. Received protocol '${url.protocol}'`;
   return msg;

test/es-module/test-esm-dynamic-import.js

@@ -62,8 +62,8 @@ function expectFsNamespace(result) {
   if (common.isWindows) {
     const msg =
       'Only file and data URLs are supported by the default ESM loader. ' +
-      'Absolute Windows paths without prefix are not valid URLs, ' +
-      "consider using 'file://' prefix. Received protocol 'c:'";
+      'On Windows, absolute paths must be valid file:// URLs. ' +
+      "Received protocol 'c:'";
     expectModuleError(import('C:\\example\\foo.mjs'),
                       'ERR_UNSUPPORTED_ESM_URL_SCHEME',
                       msg);