fix(library/scope): warning message, and old comment

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/kernel_bindings): missing kind in lean_kind

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(kernel/level): add (trivial) case for is_geq predicate: l >= 0 for any l

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(doc/lua): typos in the documentation

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>