RT# 69026: PPI docs mention PPI::Token::Bareword, but it does not exist

The PPI docs showed an example tree structure supposedly generated by
parsing some Perl document, but the example had gotten out of synch with
reality, showing two element types that don't actually exist.

This commit fixes that by replacing the erroneous element classes with
those actually parsed.

lib/PPI.pm

@@ -541,8 +541,8 @@ via the included L<PPI::Dumper>).
   PPI::Document
     PPI::Token::Comment                '#!/usr/bin/perl\n'
     PPI::Token::Whitespace             '\n'
-    PPI::Statement::Expression
-      PPI::Token::Bareword             'print'
+    PPI::Statement
+      PPI::Token::Word                 'print'
       PPI::Structure::List             ( ... )
         PPI::Token::Whitespace         ' '
         PPI::Statement::Expression
@@ -551,8 +551,8 @@ via the included L<PPI::Dumper>).
       PPI::Token::Structure            ';'
     PPI::Token::Whitespace             '\n'
     PPI::Token::Whitespace             '\n'
-    PPI::Statement::Expression
-      PPI::Token::Bareword             'exit'
+    PPI::Statement
+      PPI::Token::Word                 'exit'
       PPI::Structure::List             ( ... )
       PPI::Token::Structure            ';'
     PPI::Token::Whitespace             '\n'
@@ -568,14 +568,14 @@ whitespace. Here it is again, sans the distracting whitespace tokens.
 
   PPI::Document
     PPI::Token::Comment                '#!/usr/bin/perl\n'
-    PPI::Statement::Expression
-      PPI::Token::Bareword             'print'
+    PPI::Statement
+      PPI::Token::Word                 'print'
       PPI::Structure::List             ( ... )
         PPI::Statement::Expression
           PPI::Token::Quote::Double    '"Hello World!"'
       PPI::Token::Structure            ';'
-    PPI::Statement::Expression
-      PPI::Token::Bareword             'exit'
+    PPI::Statement
+      PPI::Token::Word                 'exit'
       PPI::Structure::List             ( ... )
       PPI::Token::Structure            ';'