docs: enhance reactor context propagation documentation #10219
Description
We might want to add [in] core, a note on how to add the context in the middle of the reactive chain:
PropagatedContext propagatedContext = PropagatedContext.get();
mono.contextWrite(ctx -> ReactorPropagation.addPropagatedContext(ctx, propagatedContext))
Originally posted by @dstepanov in micronaut-projects/micronaut-reactor#385 (comment)