support on hover for `+=` and so on

[asukaminato0721]

Describe the Bug

now we have x + 1, but don't havex += 1 .

Sandbox Link

No response

(Only applicable for extension issues) IDE Information

No response

[asukaminato0721]

#claim

[github-actions]

@asukaminato0721 you've claimed this issue — it's now assigned to you. Thanks for picking it up! 🎉