pw_chrono_stl: small docs fixup

Change-Id: I2665b848676166fe0d312ce543900dace8395a5e
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/26340
Reviewed-by: Armando Montanez <amontanez@google.com>
Commit-Queue: Ewout van Bekkum <ewout@google.com>
diff --git a/pw_chrono_stl/docs.rst b/pw_chrono_stl/docs.rst
index 8160deb..3ba23ba 100644
--- a/pw_chrono_stl/docs.rst
+++ b/pw_chrono_stl/docs.rst
@@ -22,5 +22,7 @@
 Build targets
 -------------
 The GN build for ``pw_chrono_stl`` has one target: ``system_clock``.
-The ``system_clock`` target provides the ``pw_chrono_stl/system_clock.h`` header
-and the backend for the ``pw_chrono:system_clock``.
+The ``system_clock`` target provides the
+``pw_chrono_backend/system_clock_config.h`` and
+``pw_chrono_backend/system_clock_inline.h`` headers and the backend for the
+``pw_chrono:system_clock``.