Add class comment for Signal/BaseSignal

[Kietyo]

Describe the bug

I'm confused about how the signal stuff works, would be great if the class itself had header comments.

Annoyment level

How annoyed are you in a scale of 1-3 because this shitty code doesn't work properly

• [x] 1 - No rush from my side
• [ ] 2 - It is inconvenient, but I can circumvent the issue for now
• [ ] 3 - FUUUU
• [ ] 4

Payment

sponsor.