combobox: Don't special-case RTL child positions anymore
combobox: Don't special-case RTL child positions anymore

If you want to get rounded corners on an hbox, instead of
  :first-child {
    border-top-left-radius: 5px;
    border-bottom-left-radius: 5px;
  }
  :last-child {
    border-top-right-radius: 5px;
    border-bottom-right-radius: 5px;
  }
you now need to write:
  :first-child, :last-child:dir(rtl) {
    border-top-left-radius: 5px;
    border-bottom-left-radius: 5px;
  }
  :last-child, :first-child:dir(rtl)
  {
    border-top-right-radius: 5px;
    border-bottom-right-radius: 5px;
  }

ahodesuka/gtk,jadahl/gtk,msteinert/gtk,jessevdk/gtk,chergert/gtk,ahodesuka/gtk,alexlarsson/gtk,bratsche/gtk-,Lyude/gtk-,davidgumberg/gtk,davidgumberg/gtk,chergert/gtk,jessevdk/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,davidt/gtk,davidt/gtk,davidgumberg/gtk,alexlarsson/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,davidgumberg/gtk,grubersjoe/adwaita,davidgumberg/gtk,msteinert/gtk,jigpu/gtk,jessevdk/gtk,Distrotech/gtk2,jadahl/gtk,grubersjoe/adwaita,Distrotech/gtk2,jigpu/gtk,Sidnioulz/SandboxGtk,Distrotech/gtk2,Sidnioulz/SandboxGtk,davidt/gtk,Adamovskiy/gtk,ebassi/gtk,Adamovskiy/gtk,davidgumberg/gtk,davidt/gtk,bratsche/gtk-,jessevdk/gtk,msteinert/gtk,msteinert/gtk,chergert/gtk,Lyude/gtk-,alexlarsson/gtk,alexlarsson/gtk,Distrotech/gtk2,ahodesuka/gtk,chergert/gtk,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,chergert/gtk,jadahl/gtk,grubersjoe/adwaita,davidt/gtk,chergert/gtk,ebassi/gtk,Sidnioulz/SandboxGtk,bratsche/gtk-,grubersjoe/adwaita,ebassi/gtk,Distrotech/gtk2,Lyude/gtk-,ebassi/gtk,ahodesuka/gtk,Adamovskiy/gtk,jadahl/gtk,msteinert/gtk,davidgumberg/gtk,grubersjoe/adwaita,Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,chergert/gtk,jigpu/gtk,chergert/gtk,jessevdk/gtk,alexlarsson/gtk,jadahl/gtk,ebassi/gtk,msteinert/gtk,Adamovskiy/gtk,ahodesuka/gtk,bratsche/gtk-,Distrotech/gtk2,jadahl/gtk,bratsche/gtk-,jigpu/gtk,jigpu/gtk,jigpu/gtk,Lyude/gtk-,davidgumberg/gtk,davidt/gtk,Lyude/gtk-,jessevdk/gtk,jessevdk/gtk,grubersjoe/adwaita,Adamovskiy/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,ahodesuka/gtk,jigpu/gtk,alexlarsson/gtk,Lyude/gtk-,alexlarsson/gtk,ebassi/gtk,alexlarsson/gtk,jadahl/gtk,Adamovskiy/gtk,bratsche/gtk-