docs: remove links to docs as onion services

Since they don't exist anymore.

Closes #28662.

README.md

@@ -43,9 +43,7 @@ Documentation
 --------------
 
 More extensive documentation can be found in the ./docs directory,
-and online at [sbws.rtfd.io](https://sbws.readthedocs.io) and
-[this onion service](http://d7pxflytfsmz6uh3x7i2jxzzwea6nbpmtsz5tmfkcin5edapaig5vpyd.onion/)
-([v2](http://sdmb3rfvp3wadu6y.onion/)).
+and online at [sbws.rtfd.io](https://sbws.readthedocs.io).
 
 ## License