[docs] fix httpsig repo typo (#3426)

docs/federation/http_signatures.md

@@ -6,7 +6,7 @@ GoToSocial will also sign all outgoing `GET` and `POST` requests that it makes t
 
 This behavior is the equivalent of Mastodon's [AUTHORIZED_FETCH / "secure mode"](https://docs.joinmastodon.org/admin/config/#authorized_fetch).
 
-GoToSocial uses the [superseriousbusiness/httpsig](https://github.com/superseriousbusiness/httpsign) library (forked from go-fed) for signing outgoing requests, and for parsing and validating the signatures of incoming requests. This library strictly follows the [Cavage http signature RFC](https://datatracker.ietf.org/doc/html/draft-cavage-http-signatures-12), which is the same RFC used by other implementations like Mastodon, Pixelfed, Akkoma/Pleroma, etc. (This RFC has since been superceded by the [httpbis http signature RFC](https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-message-signatures), but this is not yet widely implemented.)
+GoToSocial uses the [superseriousbusiness/httpsig](https://github.com/superseriousbusiness/httpsig) library (forked from go-fed) for signing outgoing requests, and for parsing and validating the signatures of incoming requests. This library strictly follows the [Cavage http signature RFC](https://datatracker.ietf.org/doc/html/draft-cavage-http-signatures-12), which is the same RFC used by other implementations like Mastodon, Pixelfed, Akkoma/Pleroma, etc. (This RFC has since been superceded by the [httpbis http signature RFC](https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-message-signatures), but this is not yet widely implemented.)
 
 ## Query Parameters