__getitem__ on search results operates on root not result

[braingram]

Description of the problem

I expected providing a key/index to a search result would descend relative to the search result. However it's unclear what it's doing (see the example below).

The documentation doesn't make it clear what "descending" into a search result means:
https://asdf.readthedocs.io/en/latest/asdf/features.html#descending-into-child-nodes

Example of the problem

>>> import asdf
>>> af = asdf.AsdfFile({"a": 1, "b": {"c": [1, 2, 3]}})
>>> af.search("c")
root (AsdfObject)
└─b (dict)
  └─c (list): [1, 2, 3]
>>> af.search("c")[0]   # I expected this to return 1 since it's the 0th item in "c"
KeyError: 0
>>> af.search()["a"]   # roughly matches the example, suggesting indexing is relative to the root
a (int): 1
>>> af.search("c")["a"]  # maybe this makes sense since there's no "c" in "a"
No results found.
>>> af.search("c")["b"]  # maybe this should return "c"?
No results found.

System information

asdf version: main
python version: 3.10
operating system: mac