Add details to sync-metadata-storage's help

People might think this command synchronizes the database with migration
files, when it merely synchronizes it with the definition of the
metadata table.

lib/Doctrine/Migrations/Tools/Console/Command/SyncMetadataCommand.php

@@ -20,7 +20,10 @@ protected function configure(): void
             ->setAliases(['sync-metadata-storage'])
             ->setDescription('Ensures that the metadata storage is at the latest version.')
             ->setHelp(<<<'EOT'
-The <info>%command.name%</info> command updates metadata storage the latest version.
+The way metadata is stored in the database can change between releases.
+The <info>%command.name%</info> command updates metadata storage to the latest version,
+ensuring it is ready to receive migrations generated by the current version of Doctrine Migrations.
+
 
     <info>%command.full_name%</info>
 EOT);