增加对歌词的搜索功能

[TianMiao]

仅仅提交一个建议。Submit just one proposal.

在你提交此建议前请注意：Please note before you submit this proposal:

• 详细阅读椒盐音乐帮助内容（应用设置-帮助）。Read more about the SaltPlayer help content (app Settings - Help).

反馈时候请注意：When giving feedback, please note:

• 尽量详细的描述。Be as detailed as possible.
• 不接收任何 UI 样式调整相关的反馈，出现此类 issue 会被关闭（如 “我不喜欢此设计” 、“我觉得这样设计更好” 、“还没原来好看” 等等类似反馈）。Do not receive any feedback on UI style changes, and the issue will be closed (" I don't like this design ", "I think this design is better", "it's not as good as the original", etc.).

建议内容 The proposals

<在此输入你的建议 Enter your suggestions here>
在扫描歌曲时，向数据库中添加歌曲的歌词内容，在搜索时一并进行搜索