docs: `trigger` command outputs --help content related to `log` command

[haysclark]

trigger cmd needs some documentation

Code: https://github.com/jenkins-x-plugins/jx-admin/blob/main/pkg/cmd/trigger/trigger.go#L38-L50

Current output:

~jx admin trigger -h                                                                                                                                                                     Views the boot Job logs in the cluster

Usage:
  jx-admin trigger [flags]

Aliases:
  trigger, rerun

Examples:
  * views the current boot logs
  
    ```bash
    jx-admin log
    ```

Flags:
  -b, --batch-mode          Runs in batch mode without prompting for user input
      --commit-sha string   the git commit SHA to filter jobs by
  -h, --help                help for trigger
      --log-level string    Sets the logging level. If not specified defaults to $JX_LOG_LEVEL
  -n, --namespace string    the namespace where the boot jobs run. If not specified it will look in: jx-git-operator and jx
  -s, --selector string     the selector of the boot Job pods (default "app=jx-boot")
      --verbose             Enables verbose output. The environment variable JX_LOG_LEVEL has precedence over this flag and allows setting the logging level to any value of: panic, fatal, error, warn, info, debug, trace