Update docs to contain mentioning of `SSD1681` and `WeAct`

**Describe the problem you have/What new integration you would like**
I tend to browse the docs of esphome to decide on which components to buy for a certain project.

Not finding a component usually leads to me using a different one instead.

This time (due to only 3 epaper displays being visible on the docs preview pages) i digging a bit deeper and first searched for what displays are on the market and somewhat cheap available.
I saw that the WeAct epaper displays are available, but not listed as compatible in the esphome docs.
Then i searched through the issues and feature requests repo of esphome, just to see if someone requested a component for it yet and here we go: https://github.com/esphome/feature-requests/issues/2697

Since they seem to work as per @latonita, it would be great if they could be mentioned in the docs with the brands name that sells the hardware display component (`WeAct`) and also with the controllers name (`SSD1681`).
This way everyone can easily see that they should work out-of-the-box.

**Please describe your use case for this integration and alternatives you've tried:**

see above section

**Additional context**

see above section