[Ada] Document Aggregate_Individually_Assign as a configuration pragma

[Pierre-Marie de Rodat via Gcc-patches]

Pragma Aggregate_Individually_Assign was apparently forgotten to be
listed in the GNAT User's Guide as a configuration pragma.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * doc/gnat_ugn/the_gnat_compilation_model.rst (Configuration
        Pragmas): Add Aggregate_Individually_Assign; otherwise the list
        is complete except for some obsoleted pragmas, which most likely
        are intentionally omitted.
        * gnat_ugn.texi: Regenerate.
diff --git a/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst b/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
--- a/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
+++ b/gcc/ada/doc/gnat_ugn/the_gnat_compilation_model.rst
@@ -1402,6 +1402,7 @@ recognized by GNAT::
      Ada_12
      Ada_2012
      Ada_2022
+     Aggregate_Individually_Assign
      Allow_Integer_Address
      Annotate
      Assertion_Policy


diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi
--- a/gcc/ada/gnat_ugn.texi
+++ b/gcc/ada/gnat_ugn.texi
@@ -2808,6 +2808,7 @@ Ada_2005
 Ada_12
 Ada_2012
 Ada_2022
+Aggregate_Individually_Assign
 Allow_Integer_Address
 Annotate
 Assertion_Policy