textview: Update adjustment usage for sealing
textview: Update adjustment usage for sealing

Also rename all variables named "adj" to "adjustment", like they're
called everywhere else.

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