Document feedback.new_issue_url & feedback.existing_issues_url

Signed-off-by: Michael Telatynski <[email protected]>

docs/config.md

@@ -355,6 +355,8 @@ If you run your own rageshake server to collect bug reports, the following optio
 2. `uisi_autorageshake_app`: If a user has enabled the "automatically send debug logs on decryption errors" flag, this option will be sent
    alongside the rageshake so the rageshake server can filter them by app name. By default, this will be `element-auto-uisi`
    (in contrast to other rageshakes submitted by the app, which use `element-web`).
+3. `existing_issues_url`: URL for where to find existing issues.
+4. `new_issue_url`: URL for where to sub\*\*\*\*mit new issues.
 
 If you would like to use [Sentry](https://sentry.io/) for rageshake data, add a `sentry` object to your config with the following values: