Add option scrolllock:mod3
This maps Scroll_Lock to Mod3, effectively enabling this virtual modifier if the option is provided.
In the second commit the mapping gets removed from the br(abnt2)
layout where it has no place (by default). There's nothing about that layout that requires it so let's punt it to an option as it was somewhat intended in the original bug [1] (see also !555 (closed) and !112 (merged)). cc @cfgnunes
[1] https://bugs.freedesktop.org/show_bug.cgi?id=28972
I can't think of a better name than scrolllock:mod3
...
Arguably, this should be incorporated that the default keymap doesn't include this (otherwise unmapped) ScrollLock
virtual modifier. Instead we should pull in the compat:misc
and compat:ledscroll
parts. Without the modifier_map
statement this virtual modifier doesn't do anything...