[listchan] duplicate channel names joining first about bitlbee-discord

[sm00th]

Workaround: setting server_prefix_len to non-zero

[digitalcircuit]

Now that listchan is in master, should server_prefix_len be set to non-zero by default? Though the underlying bug here should also be fixed, this would help distinguishing identical channel names across servers when the topic's changed from default.

[sm00th]

Looked at it today and that might be the only viable solution at this point. The other solution would be to add indexes to bitlbee's bee_chat_info, but it is probably not a good idea. Bitblee rightfully doesn't expect a single account to have multiple channels with the same name, so it is plugin's job to ensure they are unique.

I'll set server_prefix_len to 3 by default and update the README explaining this.

[sm00th]

I'll also be adding '_' to the end of channel names till we get a unique name, so that even if a user has 2 servers with the same first 3 letters in the name the channel name will still be unique.