Support for muted icons for pulseaudio devices/ports

[locked-out]

This PR enables users to specify alternate pulseaudio icons for when a sink is muted.
For example, adding a headphone-muted entry into a format-icons object will use the corresponding icon when the current sink is a headphone port and is muted.
Users can also specify [current_sink_name]-muted, [port]-muted or default-muted icons

When not muted, behavior is unchanged.
When muted, icons are searched for in the following order:

• [current_sink_name]-muted
• [current_sink_name] (Existing behavior)
• [default_source_name] (Existing behavior)
• [port]-muted
• [port] (Existing behavior)
• default-muted
• default (Existing behavior)

Feedback welcome, this is the least intrusive way I thought of to include this feature that I wanted personally.

Example config

  "pulseaudio": {
      "format": "{icon} {volume}%",
      "format-muted": "{icon} Muted",

      "format-icons": {
          "headphone":        "󰋋",
          "headphone-muted":  "󰟎",
          "portable":         "󰏲",
          "portable-muted":   "󰷯",
          "car":              "󰄋",
          "car-muted":        "󰸜",
          "default": ["", "", ""],
          "default-muted":    "󰸈"
      }
  }

Example results

[Alexays]

Nice, can you update the man and wiki?

[locked-out]

Done 👍