docs: Update docstring of CrawlerInstrumentor (apify#1697)

### Description

- Update dostring for `request_handling_instrumentation` argument of
`CrawlerInstrumentor`

Author: Pijukatel

src/crawlee/otel/crawler_instrumentor.py

@@ -33,8 +33,8 @@ def __init__(
         Args:
             instrument_classes: List of classes to be instrumented - all their public methods and coroutines will be
                 wrapped by generic instrumentation wrapper that will create spans for them.
-            request_handling_instrumentation: Handpicked most interesting methods to instrument in the request handling
-                pipeline.
+            request_handling_instrumentation: When `True`, the most relevant methods in the request handling pipeline
+                will be instrumented. When `False`, no request handling instrumentation will be done.
         """
         self._tracer = get_tracer(__name__)