talkatu/talkatu

Add a missing prototype to talkatuscrolledwindow.h

2020-08-20, Gary Kramlich
3b6c635cef20
Add a missing prototype to talkatuscrolledwindow.h

Add a prototype for talkatu_scrolled_window_page_down as it was missed initially.

Reviewed at https://reviews.imfreedom.org/r/73/
Talkatu is versioned in [mercurial](https://www.mercurial-scm.org/) and is
available on [bitbucket](https://bitbucket.org/pidgin/talkatu).
All contributions are provided via pull requests to the bitbucket repository.