[BUG] govc ls -xml fails with "xml: unsupported type"

[CarstenGrohmann]

Describe the bug
govc ls -xml returns an error but govc ls -json don't. The help for govc ls says that -json and -xml are valid options.

# ./govc ls -xml / 
./govc: xml: unsupported type: func(context.Context, *vim25.Client) error

# ./govc ls -json /
{
  "elements": [
    {
      "Path": "/MyDC",
      "Object": {
        "Self": {
          "Type": "Datacenter",
          "Value": "datacenter-1"
        },
        "Value": null,
[...]

# ./govc ls -h
Usage: ./govc ls [OPTIONS] [PATH]...

List inventory items.

Examples:
  govc ls -l '*'
  govc ls -t ClusterComputeResource host
  govc ls -t Datastore host/ClusterA/* | grep -v local | xargs -n1 basename | sort | uniq

Options:
  -L=false               Follow managed object references
  -cert=                 Certificate [GOVC_CERTIFICATE]
  -dc=                   Datacenter [GOVC_DATACENTER]
  -debug=false           Store debug logs [GOVC_DEBUG]
  -dump=false            Enable Go output
  -i=false               Print the managed object reference
  -json=false            Enable JSON output
  -k=false               Skip verification of server certificate [GOVC_INSECURE]
  -key=                  Private key [GOVC_PRIVATE_KEY]
  -l=false               Long listing format
  -persist-session=true  Persist session to disk [GOVC_PERSIST_SESSION]
  -t=                    Object type
  -tls-ca-certs=         TLS CA certificates file [GOVC_TLS_CA_CERTS]
  -tls-known-hosts=      TLS known hosts file [GOVC_TLS_KNOWN_HOSTS]
  -trace=false           Write SOAP/REST traffic to stderr
  -u=                    ESX or vCenter URL [GOVC_URL]
  -verbose=false         Write request/response data to stderr
  -vim-namespace=vim25   Vim namespace [GOVC_VIM_NAMESPACE]
  -vim-version=7.0       Vim version [GOVC_VIM_VERSION]
  -xml=false             Enable XML output

To Reproduce
Steps to reproduce the behavior:

1. run ./govc ls -json /
2. run ./govc ls -xml /

Expected behavior
./govc ls -xml / return the content in XML.

Affected version

# ./govc version -l
Build Version: 0.30.2
Build Commit: 9078b0b4
Build Date: 2023-02-01T04:38:27Z

[github-actions]

Howdy 🖐   CarstenGrohmann ! Thank you for your interest in this project. We value your feedback and will respond soon.

If you want to contribute to this project, please make yourself familiar with the CONTRIBUTION guidelines.