✨ LSP Event & Notification Handling

[thecoolwinter]

Description

Language servers can send clients (CodeEdit) notifications and events we should respond to. These include logging ([1], [2]), show messages, showing progress, opening a file and a lot more.

Right now our client implementation receives notifications and events but does nothing with them. This issue is a tracking issue for implementing handlers for each capability a server might use.

[thecoolwinter]

For anyone looking to take this on, create or find an issue related to each notification / event that needs implementing and paste the URL of this issue in that one to link it. Once we've implemented all LSP events and notifications we'll close this issue.