fix(frontends/lean/elaborator): remove duplicate entries in flyinfo data

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(kernel/formatter): fixes #21

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(frontends/lean): add hack for flycheck

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