Custom typing notification and component

[brichet]

This PR allows a custom notification for a "writing" user.

Fixes #263

Changes

@jupyter/chat

• the ChatModel.IWriter interface allows a typingIndicator?: string, which is used in place of the default 'is writing' indication
• the chat widget has a new property called writerComponent, that can contain a react component to display after each user writing notification

jupyterlab-chat

• the user structure in the document awareness can be populated with an optional typingIndicator when the isWriting property is set
• a new plugin provides the writerComponent object, to allow third party extensions to add a component.

Example

Using of the new indicator and component with jupyter-ai.

output.webm

[github-actions]

👈 Launch a Binder on branch brichet/jupyter-chat/custom_typing_notification

[jtpio]

Nice, thanks @brichet for working on this!

Looks like it picked up some conflicts, likely after the merge of #262.

[brichet]

Looks like it picked up some conflicts, likely after the merge of #262.

Indeed.
I'll wait for #275 to be merged before fixing it, to avoid future conflicts.