Update faq.md with info about potencial transition "flash"

[distante]

[blazoncek]

Hi. Thanks, but the description is misleading. Please avoid word "flicker" as it has completely different meaning than used here. You are also giving incorrect assumption that transition is at the issue when in fact it is starting color (black) and ending color (non-black), causing an apparent flash. More accurate description should mention color transition and the influence of it.