Prefer symbolic icon for volume

[newhoa]

Currently ayatana-indicator-sound prefers non-symbolic icons. So if an icon theme has audio-volume-low-symbolic in its symbolic folder and audio-volume-low in its 48/status folder, it will choose the 48px non-symbolic icon.

Panels can be light or dark and preferring a symbolic icon would be more compatible with many themes and be much clearer and more legible with any style.

Here and here look like relevant spots where this might need to be addressed. I'm not familiar with the code so I'm not sure if changing the names would be enough or if more would need to be added (like if using non-symbolic as fallbacks or limiting the maximum size).

[tari01]

It is up to the theme to provide icons that control what Ayatana system indicators present to the user. These icons should always end with -panel.

For example, this is the search order for the audio-volume-low icon:

1. audio-volume-low-panel-symbolic
2. audio-volume-low-panel
3. audio-volume-low
4. audio-volume
5. audio

The first full match will be the icon that you see (as an alternative, audio-volume-low-panel-symbolic can be a symlink to audio-volume-low-panel). I'm closing this as already implemented.