docs: fix mistake in ACME challenge type comment
@@ -123,7 +123,7 @@ tls_client_auth_mode: relaxed
tls_letsencrypt_cache_dir: /var/lib/headscale/cache
# Type of ACME challenge to use, currently supported types:
-# HTTP-01 or TLS_ALPN-01
+# HTTP-01 or TLS-ALPN-01
# See [docs/tls.md](docs/tls.md) for more information
tls_letsencrypt_challenge_type: HTTP-01
# When HTTP-01 challenge is chosen, letsencrypt must set up a
