[Geany] scrolling down to the bottom

[John Gabriele]

When searching in a document, it's nice how the window view gets
centered on the search term (when the search term is further down the
page, out of view from where you started).

However, when scrolling with the mouse, if one scrolls all the way to
the bottom, you end up with a mostly-blank window, with only the last
line showing at the top. It would probably be more useful if, when
scrolling all the way down, the view were left in the same way as if a
search had landed you at the last line of the doc (that is, with the
last line somewhere near the middle of the window). Or possibly with
the view centered, like what "Scroll to current line" does.

---John