Use compact test comment under @pytest.mark.parametrize for each test case

[bobleesj]

Suggested by by @sbillinge:

---

let's not modify this PR again, but I do wonder whether it would be more compact as

        (  # C1: Target value is in the xarray and xtype is identical, expect exact index match
            {
                "wavelength": 4 * np.pi,
                "xarray": np.array([30.005, 60]),
                "yarray": np.array([1, 2]),
                "xtype": "tth",
            },
            {
                "xtype": "tth",
                "value": 30.005,
            },
            [0],
        ),

than the current

    # C1: Target value is in the xarray and xtype is identical, expect exact index match
        (
            {
                "wavelength": 4 * np.pi,
                "xarray": np.array([30.005, 60]),
                "yarray": np.array([1, 2]),
                "xtype": "tth",
            },
            {
                "xtype": "tth",
                "value": 30.005,
            },
            [0],
        ),

Please see @bobleesj's response in #273 (comment)_