add missing link to the QUIC experiment

License: MIT
Signed-off-by: Marten Seemann <martenseemann@gmail.com>

docs/experimental-features.md

@@ -25,6 +25,7 @@ the above issue.
 - [Plugins](#plugins)
 - [Directory Sharding / HAMT](#directory-sharding-hamt)
 - [IPNS PubSub](#ipns-pubsub)
+- [QUIC](#quic)
 
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