search bar in sidebar of docs must be floating (css)

**What is the current behaviour?**

**Currently Search bar, version drop down and mongoose logo does not have CSS floating property .**
**Hence when we scroll down sidebar those things go disappear**

**What is the expected behavior?**

**Ww must make them floating at the top, so that when we'll scroll down the sidebar they wont go disappear**

https://mongoosejs.com/docs/