docs: clarify usage for multiple apps

docs/deployment/logs.md

@@ -2,7 +2,7 @@
 
 ```
 logs <app> [-h] [-t] [-n num] [-q] [-p process]  # Display recent log output
-logs:failed <app>                                # Shows the last failed deploy logs for an app
+logs:failed [<app>]                              # Shows the last failed deploy logs
 ```
 
 ## Usage
@@ -44,3 +44,9 @@ You can retrieve these logs by using the `logs:failed` command
 ```shell
 dokku logs:failed node-js-app
 ```
+
+You can also retrieve the failed logs for each app:
+
+```shell
+dokku logs:failed node-js-app
+```

plugins/logs/subcommands/failed

@@ -5,7 +5,7 @@ source "$PLUGIN_AVAILABLE_PATH/config/functions"
 set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 
 cmd-logs-failed() {
-  declare desc="shows the last failed deploy logs for an app"
+  declare desc="shows the last failed deploy logs"
   declare cmd="logs:failed" argv=("$@"); [[ ${argv[0]} == "$cmd" ]] && shift 1
   declare APP="$1"
   local DOKKU_SCHEDULER