Better errors on broken configuration

[lovesegfault]

Currently something is wrong with my waybar config, and I'm not sure why as waybar doesn't start and the CLI tells me only this:

❯ waybar
[2019-11-16 23:46:06.853] [info] Resources files: /home/bemeurer/.config/waybar/config, /home/bemeurer/.config/waybar/style.css
in Json::Value::find(begin, end): requires objectValue or nullValue

{
  "backlight": {
    "format": "{percent}% {icon}",
    "format-icons": [
      "",
      ""
    ],
    "on-scroll-down": "/nix/store/nqpp073v0vxmws2qwkd4gvga9hsz6kdh-light-1.2/bin/light -U 1",
    "on-scroll-up": "/nix/store/nqpp073v0vxmws2qwkd4gvga9hsz6kdh-light-1.2/bin/light -A 1"
  },
  "battery": {
    "format": "{capacity}% {icon}",
    "format-alt": "{time} {icon}",
    "format-charging": "{capacity}% ",
    "format-icons": [
      "",
      "",
      "",
      "",
      ""
    ],
    "format-plugged": "{capacity}% ",
    "states": {
      "critical": 15,
      "good": 90,
      "warning": 30
    }
  },
  "clock": {
    "format": "{:%F %T %Z}",
    "tooltip-format": "{:%Y-%m-%d | %H:%M}"
  },
  "layer": "top",
  "modules-left": [
    "sway/workspaces",
    "sway/mode"
  ],
  "modules-right": [
    "backlight",
    "battery",
    "clock"
  ],
  "sway/mode": "<span style=\"italic\">{}</span>"
}

It'd be nice if the errors on config failures were more clear/informative.