Notebooks GA launch: /code-search/ page updates

Created by: marybelzer

Notebooks are going GA on April 27. To bring visibility to the feature, I'd like to add a module to it on our Code Search page (https://about.sourcegraph.com/code-search/) with some text + a GIF / capture

🔗Copy doc → Paragraph text only Location: between a Search Engine Build for Code and Move faster with Sourcegraph. Text to the left, video to the right. 📹 Link to video: https://drive.google.com/file/d/1v_dJjX0olWQEmp51ADSpTVF08Yf3u4gl/view?usp=sharing [confirmed it will NOT be hosted on youtube] No meta updates

Asana: https://app.asana.com/0/1200095757619647/1202015295852699/f