[Geany] hidden pref: show_editor_scrollbars (and also the horizontal scroll)

[John Gabriele]

Just noticed another minor display (or maybe doc) issue: if I set the
hidden pref show_editor_scrollbars=false, contrary to the docs, the
scrollbars never appear -- even when the document is longer than what
the view can display. I can still scroll down via the scroll wheel
though.

Interesting sidenote, Geany's horizontal scrollbar at the bottom is a
bit odd in the way that it lets you scroll way out to the right even
if you don't have any long lines. It tends to make me think I've got a
really long line somewhere in my doc. One way I've seen this feature
work in other editors is, the size of the scrollbar slider grippy
thingy at the bottom varies depending on the max line length *of only
the lines currently visible in the view*. More commonly though, the
size of the slider thingy just gets set based on the length of the
longest line in the whole doc, and that works very well.

---John