docs: insert space between original help message and suffix (#48)

snakemake_interface_common/plugin_registry/plugin.py

@@ -160,7 +160,7 @@ def register_cli_args(self, argparser):
                 kwargs["nargs"] = "+"
                 kwargs["type"] = str
                 kwargs["help"] += (
-                    "Can be specified multiple times to set different "
+                    " Can be specified multiple times to set different "
                     "values for different tags."
                 )
                 kwargs["metavar"] = f"[TAG::]{kwargs['metavar']}"