[gcc r12-1496] [Ada] Clarify the documentation of -gnaty0 style check option

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:a85d1c14073af24e79f19abf50271e219511054d

commit r12-1496-ga85d1c14073af24e79f19abf50271e219511054d
Author: Sergey Rybin <rybin@adacore.com>
Date:   Wed Feb 17 16:31:08 2021 +0300

    [Ada] Clarify the documentation of -gnaty0 style check option
    
    gcc/ada/
    
            * doc/gnat_ugn/building_executable_programs_with_gnat.rst:
            Instead of referring to the formatting of the Ada examples in
            Ada RM add use the list of checks that are actually performed.
            * gnat_ugn.texi: Regenerate.

Diff:
---
 .../building_executable_programs_with_gnat.rst      | 14 ++++++++++++--
 gcc/ada/gnat_ugn.texi                               | 21 +++++++++++++++++++--
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
index 3da03dfd307..63b3f17d402 100644
--- a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
+++ b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst
@@ -4629,8 +4629,18 @@ checks to be performed. The following checks are defined:
   in the string after :switch:`-gnaty`
   then proper indentation is checked, with the digit indicating the
   indentation level required. A value of zero turns off this style check.
-  The general style of required indentation is as specified by
-  the examples in the Ada Reference Manual. Full line comments must be
+  The rule checks that the following constructs start on a column that is
+  a multiple of the alignment level:
+
+  * beginnings of declarations (except record component declarations)
+    and statements;
+
+  * beginnings of the structural components of compound statements;
+
+  * ``end`` keyword that completes the declaration of a program unit declaration
+    or body or that completes a compound statement.
+
+  Full line comments must be
   aligned with the ``--`` starting on a column that is a multiple of
   the alignment level, or they may be aligned the same way as the following
   non-blank line (this is useful when full line comments appear in the middle
diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi
index e6078e67e9b..78814c3a5d9 100644
--- a/gcc/ada/gnat_ugn.texi
+++ b/gcc/ada/gnat_ugn.texi
@@ -13227,8 +13227,25 @@ If a digit from 1-9 appears
 in the string after @code{-gnaty}
 then proper indentation is checked, with the digit indicating the
 indentation level required. A value of zero turns off this style check.
-The general style of required indentation is as specified by
-the examples in the Ada Reference Manual. Full line comments must be
+The rule checks that the following constructs start on a column that is
+a multiple of the alignment level:
+
+
+@itemize *
+
+@item 
+beginnings of declarations (except record component declarations)
+and statements;
+
+@item 
+beginnings of the structural components of compound statements;
+
+@item 
+@code{end} keyword that completes the declaration of a program unit declaration
+or body or that completes a compound statement.
+@end itemize
+
+Full line comments must be
 aligned with the @code{--} starting on a column that is a multiple of
 the alignment level, or they may be aligned the same way as the following
 non-blank line (this is useful when full line comments appear in the middle