Adding autocomplete to methods()

I am trying to enable command-line autocomplete for various personal mfiles as well as for Matlab's native methods. For this purpose, I have the .json file below:

{
    "methods": {
        "inputs": [
            {
                "name": "fun",
                "kind": "required",
                "type": "matlabpath=*.m,*.mlx,*.c,*.cpp,*.mex*,*.mlapp"
            }
        ]
    },
    "cpwhich": {
        "inputs": [
            {
                "name": "fun",
                "kind": "required",
                "type": "matlabpath=*.m,*.mlx,*.c,*.cpp,*.mex*,*.mlapp"
            }
        ]
    },
    "ctype": {
        "inputs": [
            {
                "name": "fun",
                "kind": "required",
                "type": "matlabpath=*.m,*.mlx,*.c,*.cpp,*.mex*,*.mlapp"
            }
        ]
    },
    "chelp": {
        "inputs": [
            {
                "name": "fun",
                "kind": "required",
                "type": "matlabpath=*.m,*.mlx,*.c,*.cpp,*.mex*,*.mlapp"
            }
        ]
    }
}

This works for most of the listed functions, e.g.,

but not for methods.

It occurred to me that builtin function names and keywords may be blocked for some reason, but I have also tried replacing the methods entry with cmethods, and it still doesn't work.

    "cmethods": {
        "inputs": [
            {
                "name": "fun",
                "kind": "required",
                "type": "matlabpath=*.m,*.mlx,*.c,*.cpp,*.mex*,*.mlapp"
            }
        ]
    },

Does anyone see the problem?