Align organization wording in copyright statement

This aligns the copyright and legal notice wordig with commit
a233a603ba and pgweb commit 2d764dbc083ab8.  Backpatch down
to all supported versions.

Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Dave Page <dpage@pgadmin.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/744E414E-3F52-404C-97FB-ED9B3AA37DC8@yesql.se
Backpatch-through: 13

COPYRIGHT

@@ -1,5 +1,5 @@
 PostgreSQL Database Management System
-(formerly known as Postgres, then as Postgres95)
+(also known as Postgres, formerly known as Postgres95)
 
 Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 

doc/src/sgml/legal.sgml

@@ -11,13 +11,15 @@
  <title>Legal Notice</title>
 
  <para>
-  <productname>PostgreSQL</productname> is Copyright &copy; 1996&ndash;2025
-  by the PostgreSQL Global Development Group.
+  <productname>PostgreSQL</productname> Database Management System
+  (also known as Postgres, formerly known as Postgres95)
  </para>
 
  <para>
-  <productname>Postgres95</productname> is Copyright &copy; 1994&ndash;5
-  by the Regents of the University of California.
+  Portions Copyright &copy; 1996-2025, PostgreSQL Global Development Group
+ </para>
+ <para>
+  Portions Copyright &copy; 1994, The Regents of the University of California
  </para>
 
  <para>