Fix all flake8 warnings in docs (#211)
Fix all flake8 warnings in docs (#211)

hkariti/mopidy,SuperStarPL/mopidy,mokieyue/mopidy,SuperStarPL/mopidy,bacontext/mopidy,jcass77/mopidy,diandiankan/mopidy,jcass77/mopidy,jmarsik/mopidy,bencevans/mopidy,SuperStarPL/mopidy,mopidy/mopidy,jmarsik/mopidy,ali/mopidy,tkem/mopidy,bencevans/mopidy,tkem/mopidy,rawdlite/mopidy,abarisain/mopidy,jodal/mopidy,abarisain/mopidy,pacificIT/mopidy,rawdlite/mopidy,swak/mopidy,ali/mopidy,ali/mopidy,pacificIT/mopidy,swak/mopidy,glogiotatidis/mopidy,glogiotatidis/mopidy,jodal/mopidy,dbrgn/mopidy,liamw9534/mopidy,rawdlite/mopidy,diandiankan/mopidy,ali/mopidy,ZenithDK/mopidy,swak/mopidy,liamw9534/mopidy,vrs01/mopidy,jmarsik/mopidy,bencevans/mopidy,glogiotatidis/mopidy,jmarsik/mopidy,diandiankan/mopidy,bacontext/mopidy,vrs01/mopidy,tkem/mopidy,bacontext/mopidy,mopidy/mopidy,kingosticks/mopidy,priestd09/mopidy,woutervanwijk/mopidy,vrs01/mopidy,priestd09/mopidy,mokieyue/mopidy,hkariti/mopidy,kingosticks/mopidy,bencevans/mopidy,pacificIT/mopidy,quartz55/mopidy,ZenithDK/mopidy,jcass77/mopidy,kingosticks/mopidy,hkariti/mopidy,jodal/mopidy,bacontext/mopidy,dbrgn/mopidy,hkariti/mopidy,quartz55/mopidy,vrs01/mopidy,quartz55/mopidy,dbrgn/mopidy,woutervanwijk/mopidy,ZenithDK/mopidy,dbrgn/mopidy,mopidy/mopidy,pacificIT/mopidy,adamcik/mopidy,swak/mopidy,adamcik/mopidy,mokieyue/mopidy,glogiotatidis/mopidy,adamcik/mopidy,mokieyue/mopidy,diandiankan/mopidy,rawdlite/mopidy,priestd09/mopidy,ZenithDK/mopidy,tkem/mopidy,quartz55/mopidy,SuperStarPL/mopidy