Fix doc warnings

Author: pquentin

docs/guide/images/otel-waterfally-retry.png renamed to docs/guide/images/otel-waterfall-retry.png

@@ -5,7 +5,7 @@ You can find integration options and information on this page.
 
 
 [discrete]
-[[opentelemetry]]
+[[opentelemetry-intro]]
 === OpenTelemetry instrumentation
 
 The Python Elasticsearch client supports native OpenTelemetry instrumentation following the https://opentelemetry.io/docs/specs/semconv/database/elasticsearch/[OpenTelemetry Semantic Conventions for Elasticsearch].