Update HiddenServiceVersion in tor.1.txt to only allow one of the HS version 2 or 3
The current `HiddenServiceVersion` man page entry for `tor` is:
```
[[HiddenServiceVersion]] **HiddenServiceVersion** __version__,__version__,__...__::
```
Which reads like the config entry takes a list of version where in reality it only accept either 2 or 3.
issue