{RDBMS} az postgres flexible-server create/update: modify the error message for _pg_storage_validator

src/azure-cli/azure/cli/command_modules/rdbms/validators.py

@@ -389,13 +389,14 @@ def _pg_storage_validator(storage_gb, sku_info, tier, storage_type, iops, throug
         if instance is not None:
             original_size = instance.storage.storage_size_gb
             if original_size > storage_gb:
-                raise CLIError('Updating storage cannot be smaller than the original storage size {} GiB.'
-                               .format(original_size))
+                raise CLIError('Decrease of current storage size isn\'t supported. Current storage size is {} GiB \
+                                and you\'re trying to set it to {} GiB.'
+                               .format(original_size, storage_gb))
         if not is_ssdv2:
             storage_sizes = get_postgres_storage_sizes(sku_info, tier)
             if storage_gb not in storage_sizes:
                 storage_sizes = sorted([int(size) for size in storage_sizes])
-                raise CLIError('Incorrect value for --storage-size : Allowed values(in GiB) : {}'
+                raise CLIError('Incorrect value for --storage-size : Allowed values (in GiB) : {}'
                                .format(storage_sizes))
 
     # ssdv2 range validation