In the comment about absl::Exponential(), mention that mean = 1/lambda.

PiperOrigin-RevId: 929049316
Change-Id: I59d5efdf9b84459088c0a656ad5ec01841322580

absl/random/distributions.h

diff --git a/absl/random/distributions.h b/absl/random/distributions.h
index cfe731e..8a032df 100644
--- a/absl/random/distributions.h
+++ b/absl/random/distributions.h
@@ -283,8 +283,11 @@
 //
 // `absl::Exponential` produces a floating point number representing the
 // distance (time) between two consecutive events in a point process of events
-// occurring continuously and independently at a constant average rate. `T` must
-// be a floating point type, but may be inferred from the type of `lambda`.
+// occurring continuously and independently at a constant average rate `lambda`.
+// `T` must be a floating point type, but may be inferred from the type of
+// `lambda`.
+//
+// The mean of the distribution is 1/`lambda`.
 //
 // See https://en.wikipedia.org/wiki/Exponential_distribution.
 //