gdk: Add big fat warning about updating XSettings
gdk: Add big fat warning about updating XSettings

There's a tool to see if we forgot to update the gdk_settings_map
array, or got the offsets wrong. Mention those above the XSettings
list.

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