argument: Fix alignment of help text

When printed on the terminal the description of the command line options
is supposed to be aligned for all options. The --action_target argument
is currently not aligned with any of the other arguments. Fix this.

Change-Id: I170d445a5e490c5d6e99379b8b704992a51fca3c
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/argument.cpp b/argument.cpp
index 89c1008..d212261 100644
--- a/argument.cpp
+++ b/argument.cpp
@@ -91,19 +91,19 @@
 {
     std::cerr << "Usage: " << argv[0] << " options\n";
     std::cerr << "Options:\n";
-    std::cerr << " --help                           Print this menu\n";
-    std::cerr << " --path=<Dbus Object path>        Dbus Object path. "
+    std::cerr << " --help                                    Print this menu\n";
+    std::cerr << " --path=<Dbus Object path>                 Dbus Object path. "
                      "Ex: /xyz/openbmc_project/state/watchdog/host0\n";
-    std::cerr << " --service=<Dbus Service name>    Dbus Service name. "
-                     "Ex: xyz.openbmc_project.State.Watchdog.Host\n";
-    std::cerr << " [--target=<systemd unit>]        Systemd unit to be called "
-                     "on timeout for all actions but NONE. Deprecated, use "
-                     "--action_target instead.\n";
+    std::cerr << " --service=<Dbus Service name>             Dbus Service "
+                     "name. Ex: xyz.openbmc_project.State.Watchdog.Host\n";
+    std::cerr << " [--target=<systemd unit>]                 Systemd unit to "
+                     "be called on timeout for all actions but NONE. "
+                      "Deprecated, use --action_target instead.\n";
     std::cerr << " [--action_target=<action>=<systemd unit>] Map of action to "
                      "systemd unit to be called on timeout if that action is "
                      "set for ExpireAction when the timer expires.\n";
-    std::cerr << " [--continue]                     Continue daemon after "
-                     "watchdog timeout.\n";
+    std::cerr << " [--continue]                              Continue daemon "
+                     "after watchdog timeout.\n";
 }
 } // namespace watchdog
 } // namespace phosphor