Extend Read API documentation

[lupeterm]

Hi,
considering the use case that an object is deleted, one would probably want to delete all relationship tuples of said object.

As i said in a forum post here, the read API documentation is a little "misleading" in the sense that I originally assumed that the --relation flag is mandatory, which it isn't.

I would suggest adding a fourth example detailing that one can simply read all tuples for an object without specifying its relation nor user.
e.g.

fga tuple read --api-url=${FGA_API_URL} --store-id=${FGA_STORE_ID}  --object document:planning 

{
  "continuation_token":"",
  "tuples": [
    {
      "key": {
        "object":"document:planning",
        "relation":"viewer",
        "user":"user:bob"
      },
      "timestamp":"2025-02-25T11:39:41.626041502Z"
    },
    {
      "key": {
        "object":"document:planning",
        "relation":"owner",
        "user":"user:tom"
      },
      "timestamp":"2025-02-25T11:39:41.890193162Z"
    }
  ]
}