Fixed the TextBox template.
Fixed the TextBox template.

Previous change to add floating watermark had broken vertical scrolling.

akrisiun/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,danwalmsley/Perspex,wieslawsoltes/Perspex,wieslawsoltes/Perspex,SuperJMN/Avalonia,MrDaedra/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,susloparovdenis/Avalonia,susloparovdenis/Perspex,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,susloparovdenis/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,OronDF343/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,kekekeks/Perspex,MrDaedra/Avalonia,Perspex/Perspex,wieslawsoltes/Perspex,grokys/Perspex,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,punker76/Perspex,grokys/Perspex,kekekeks/Perspex,AvaloniaUI/Avalonia,jazzay/Perspex,OronDF343/Avalonia,jkoritzinsky/Perspex,SuperJMN/Avalonia,AvaloniaUI/Avalonia,susloparovdenis/Perspex,SuperJMN/Avalonia,SuperJMN/Avalonia,Perspex/Perspex,AvaloniaUI/Avalonia