metrics/params: fix bug preventing usage from being displayed (#5453)

dvc/command/metrics.py

@@ -284,7 +284,7 @@ def add_parser(subparsers, parent_parser):
             "(even if not found as `metrics` in `dvc.yaml`). "
             "Using -R, directories to search metrics files in "
             "can also be given."
-            "Shows all tracked metrics by default.",
+            "Shows all tracked metrics by default."
         ),
         metavar="<paths>",
     ).complete = completion.FILE

dvc/command/params.py

@@ -101,7 +101,7 @@ def add_parser(subparsers, parent_parser):
         help=(
             "Specific params file(s) to compare "
             "(even if not found as `params` in `dvc.yaml`). "
-            "Shows all tracked params by default.",
+            "Shows all tracked params by default."
         ),
         metavar="<paths>",
     ).complete = completion.FILE