Backport of Fix typo in ingress-gateway docs into release/1.17.x (#20838)

backport of commit c1e25c56db

Co-authored-by: Nathan Coleman <nathan.coleman@hashicorp.com>

website/content/docs/connect/config-entries/ingress-gateway.mdx

@@ -576,7 +576,7 @@ Specifies a list of cipher suites that gateway listeners support when negotiatin
 - Default: None
 - Data type: List of string values. Refer to the [Consul repository](https://github.com/hashicorp/consul/blob/v1.11.2/types/tls.go#L154-L169) for a list of supported ciphers.
 
-### `TSL.SDS`
+### `TLS.SDS`
 
 Specifies parameters for loading the TLS certificates from an external SDS service. Refer to [Serve custom TLS certificates from an external service](/consul/docs/connect/gateways/ingress-gateway/tls-external-service) for additional information.