test: check flag/docs consistency (#1770)

Author: piksel

docs/arguments.md

@@ -178,7 +178,7 @@ Environment Variable: WATCHTOWER_INCLUDE_RESTARTING
 Will also include created and exited containers.
 
 ```text
-            Argument: --include-stopped
+            Argument: --include-stopped, -S
 Environment Variable: WATCHTOWER_INCLUDE_STOPPED
                 Type: Boolean
              Default: false
@@ -278,7 +278,7 @@ Environment Variable: WATCHTOWER_NO_STARTUP_MESSAGE
 Run an update attempt against a container name list one time immediately and exit.
 
 ```text
-            Argument: --run-once
+            Argument: --run-once, -R
 Environment Variable: WATCHTOWER_RUN_ONCE
                 Type: Boolean
              Default: false
@@ -392,3 +392,20 @@ Environment Variable: WATCHTOWER_WARN_ON_HEAD_FAILURE
      Possible values: always, auto, never
              Default: auto
 ```
+## Programatic Output (porcelain)
+
+Writes the session results to STDOUT using a stable, machine-readable format (indicated by the argument VERSION).  
+  
+Alias for:
+
+```text
+		--notification-url logger://
+		--notification-log-stdout
+		--notification-report
+		--notification-template porcelain.VERSION.summary-no-log
+
+            Argument: --porcelain, -P
+Environment Variable: WATCHTOWER_PORCELAIN
+     Possible values: v1
+             Default: -
+```

docs/notifications.md

@@ -20,8 +20,9 @@ system, [logrus](http://github.com/sirupsen/logrus).
 -   `--notifications-hostname` (env. `WATCHTOWER_NOTIFICATIONS_HOSTNAME`): Custom hostname specified in subject/title. Useful to override the operating system hostname.
 -   `--notifications-delay` (env. `WATCHTOWER_NOTIFICATIONS_DELAY`): Delay before sending notifications expressed in seconds.
 -   Watchtower will post a notification every time it is started. This behavior [can be changed](https://containrrr.github.io/watchtower/arguments/#without_sending_a_startup_message) with an argument.
--   `notification-title-tag` (env. `WATCHTOWER_NOTIFICATION_TITLE_TAG`): Prefix to include in the title. Useful when running multiple watchtowers.
--   `notification-skip-title` (env. `WATCHTOWER_NOTIFICATION_SKIP_TITLE`): Do not pass the title param to notifications. This will not pass a dynamic title override to notification services. If no title is configured for the service, it will remove the title all together.
+-   `--notification-title-tag` (env. `WATCHTOWER_NOTIFICATION_TITLE_TAG`): Prefix to include in the title. Useful when running multiple watchtowers.
+-   `--notification-skip-title` (env. `WATCHTOWER_NOTIFICATION_SKIP_TITLE`): Do not pass the title param to notifications. This will not pass a dynamic title override to notification services. If no title is configured for the service, it will remove the title all together.
+-   `--notification-log-stdout` (env. `WATCHTOWER_NOTIFICATION_LOG_STDOUT`): Enable output from `logger://` shoutrrr service to stdout.
 
 ## [shoutrrr](https://github.com/containrrr/shoutrrr) notifications