[Accessibility] Notes should have a lighten gray in the dark mode.

When I was reading the documentation in the dark mode I've noticed that it was hard for my eyes to read the notes or the explanations because of the chosen shade for the grey.

Screenshot

Link

Hello React Navigation

Suggestion

I'd recommend choosing a light gray to make the text of notes more readable for people with low vision like me.

从 issue 中链接的 Hello React Navigation 文档页面开始，检查深色模式的样式，寻找注释或说明。将注释文本与其背景及截图进行比较，然后调整相关的灰色，使低视力人士更容易阅读文本。完成的标准是：注释在深色模式下具有更好的对比度，同时不影响页面的外观。