BUG: collect not working on YAML.load_all

[schlichtanders]

Hi there, it would be great if one could get all yamls from the iterator load_all

julia> import YAML

julia> s = """
       a: 2
       ---
       b: hello
       """
"a: 2\n---\nb: hello\n"

julia> collect(YAML.load_all(s))
ERROR: MethodError: no method matching length(::YAML.YAMLDocIterator)

using Julia 1.10.4 and YAML 0.4.11

[kescobo]

Somewhat related to #104 and #145, I think @Paalon is planning an overhaul of that part of the API