gui: Make warning titles more readable in Dark Theme
gui: Make warning titles more readable in Dark Theme

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3253

AudriusButkevicius/syncthing,kamadak/syncthing,syncthing/syncthing,imsodin/syncthing,xduugu/syncthing,le9i0nx/syncthing,TheBigBear/syncthing,lkwg82/syncthing,le9i0nx/syncthing,brgmnn/syncthing,alex2108/syncthing,kluppy/syncthing,plouj/syncthing,AudriusButkevicius/syncthing,nrm21/syncthing,AudriusButkevicius/syncthing,syncthing/syncthing,toddleish/syncthing,uok/syncthing,rumpelsepp/syncthing,kluppy/syncthing,brgmnn/syncthing,ProactiveServices/syncthing,nrm21/syncthing,nrm21/syncthing,syncthing/syncthing,TheBigBear/syncthing,uok/syncthing,le9i0nx/syncthing,jryans/syncthing,imsodin/syncthing,brgmnn/syncthing,toddleish/syncthing,syncthing/syncthing,cherylquirion/syncthing,plouj/syncthing,alex2108/syncthing,kamadak/syncthing,kluppy/syncthing,cherylquirion/syncthing,letiemble/syncthing,uok/syncthing,ProactiveServices/syncthing,wweich/syncthing,syncthing/syncthing,kamadak/syncthing,alex2108/syncthing,plouj/syncthing,letiemble/syncthing,norgeous/syncthing,Kudalufi/syncthing,jryans/syncthing,imsodin/syncthing,xduugu/syncthing,rumpelsepp/syncthing,Kudalufi/syncthing,lkwg82/syncthing,rumpelsepp/syncthing,norgeous/syncthing,alex2108/syncthing,TheBigBear/syncthing,ProactiveServices/syncthing,uok/syncthing,wweich/syncthing,lkwg82/syncthing,norgeous/syncthing,ProactiveServices/syncthing,letiemble/syncthing,brgmnn/syncthing,Kudalufi/syncthing,nrm21/syncthing,imsodin/syncthing,norgeous/syncthing,AudriusButkevicius/syncthing,wweich/syncthing,toddleish/syncthing,xduugu/syncthing,wweich/syncthing,rumpelsepp/syncthing,imsodin/syncthing,lkwg82/syncthing,syncthing/syncthing,kamadak/syncthing,plouj/syncthing,cherylquirion/syncthing,xduugu/syncthing,toddleish/syncthing,TheBigBear/syncthing,jryans/syncthing,le9i0nx/syncthing,letiemble/syncthing,kluppy/syncthing,cherylquirion/syncthing,Kudalufi/syncthing,jryans/syncthing