docs: spelling and maintenance
scan: add missing /o

While /o is not so much recommened, we're still using it. Lets be atleast consitent.
configure: Fix tiny non POSIX complaint test usage

https://bugzilla.gnome.org/show_bug.cgi?id=725663
Update the code listing style

https://bugzilla.gnome.org/show_bug.cgi?id=725505