docs: Remove PMix from MPD client list
docs: Remove PMix from MPD client list

It is no longer available on Google Play, and we didn't recommend it
2.5y ago when it was.

(cherry picked from commit d37b76f6c94a781f5b48a0e6719e08a6b69a6513)

tkem/mopidy,ZenithDK/mopidy,diandiankan/mopidy,quartz55/mopidy,ZenithDK/mopidy,swak/mopidy,SuperStarPL/mopidy,kingosticks/mopidy,adamcik/mopidy,swak/mopidy,ZenithDK/mopidy,jmarsik/mopidy,ali/mopidy,pacificIT/mopidy,bacontext/mopidy,tkem/mopidy,vrs01/mopidy,ali/mopidy,rawdlite/mopidy,quartz55/mopidy,bencevans/mopidy,mopidy/mopidy,vrs01/mopidy,ZenithDK/mopidy,ali/mopidy,bacontext/mopidy,mopidy/mopidy,jmarsik/mopidy,jodal/mopidy,jcass77/mopidy,kingosticks/mopidy,dbrgn/mopidy,rawdlite/mopidy,diandiankan/mopidy,pacificIT/mopidy,dbrgn/mopidy,SuperStarPL/mopidy,SuperStarPL/mopidy,diandiankan/mopidy,mokieyue/mopidy,pacificIT/mopidy,tkem/mopidy,mokieyue/mopidy,vrs01/mopidy,rawdlite/mopidy,kingosticks/mopidy,mokieyue/mopidy,hkariti/mopidy,bencevans/mopidy,bacontext/mopidy,tkem/mopidy,jodal/mopidy,pacificIT/mopidy,jmarsik/mopidy,bencevans/mopidy,glogiotatidis/mopidy,rawdlite/mopidy,mopidy/mopidy,dbrgn/mopidy,glogiotatidis/mopidy,adamcik/mopidy,hkariti/mopidy,vrs01/mopidy,hkariti/mopidy,hkariti/mopidy,jmarsik/mopidy,jcass77/mopidy,jodal/mopidy,glogiotatidis/mopidy,swak/mopidy,bacontext/mopidy,swak/mopidy,mokieyue/mopidy,quartz55/mopidy,ali/mopidy,SuperStarPL/mopidy,glogiotatidis/mopidy,quartz55/mopidy,diandiankan/mopidy,jcass77/mopidy,dbrgn/mopidy,bencevans/mopidy,adamcik/mopidy