Doc: Add reference to gnatfuzz integration in the test generation part

This gives a more comprehensive view of all the Tagada items that are
currently supported in a single location.

Author: leocreuse

doc/gnattest/gnattest_part.rst

@@ -933,6 +933,11 @@ Please note that all the features described bellow are experimental, and the
 interface is subject to change.
 
 GNATtest has the capability to generate test inputs for subprograms under test.
+This test generation feature is also useable in conjunction with GNATfuzz, in
+order to use GNATtest harnesses (generated or manually written) as a starting
+corpus for a fuzzing session, and to integrate inputs of interest found by
+GNATfuzz back into the test harness. For more details, see section
+:ref:`Gnattest_Gnatfuzz`.
 
 .. _Tgen_Env:
 

doc/integration/integration_part.rst

@@ -462,6 +462,8 @@ contains the name of the unit tested by the driver, and can be used to specify
 to |gcv| to only process the unit under test, by adding the switch
 :cmd-option:`[email protected]`.
 
+.. _Gnattest_Gnatfuzz:
+
 ###########################################
 Using GNATtest with GNATfuzz (experimental)
 ###########################################