Remove documentation about legacy tokens
As of today, these can no longer be created.
@@ -124,14 +124,6 @@ wee-slack script.
/python reload slack
```
-Alternatively, you can click the "Request token" button at the
-[Slack legacy token page](https://api.slack.com/custom-integrations/legacy-tokens),
-and use that instead of following the procedure above:
-
-```
-/slack register <YOUR_SLACK_TOKEN>
-```
-
The tokens you add will be stored in the option
`plugins.var.python.slack.slack_api_token`. If you don't want to store your API
token in plaintext you can use the secure features of WeeChat:
