[Feature Request]: 阅读日记时搜索关键词，并高亮显示

[Yu-Core]

Is your feature request related to a problem? Please describe. 如题，类似于ctrl + f 那样

Describe the solution you'd like A clear and concise description of what you want to happen.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context 估计不太好做，市面上的其他日记很少有这个功能