pulseaudio: export desc as a format

Signed-off-by: Niv Sardi <xaiki@evilgiggle.com>

man/waybar-pulseaudio.5.scd

@@ -82,6 +82,8 @@ Additionally you can control the volume by scrolling *up* or *down* while the cu
 
 # FORMAT REPLACEMENTS
 
+*{desc}*: Pulseaudio port's description, for bluetooth it'll be the device name.
+
 *{volume}*: Volume in percentage.
 
 *{icon}*: Icon, as defined in *format-icons*.

src/modules/pulseaudio.cpp

@@ -221,6 +221,7 @@ auto waybar::modules::Pulseaudio::update() -> void {
   }
   format_source = fmt::format(format_source, fmt::arg("volume", source_volume_));
   label_.set_markup(fmt::format(format,
+                                fmt::arg("desc", desc_),
                                 fmt::arg("volume", volume_),
                                 fmt::arg("format_source", format_source),
                                 fmt::arg("icon", getIcon(volume_, getPortIcon()))));