[preface] various further small file

- one full stop should be a semicolon
- removed trailing slash in http://perl.org/
- 'the compiler' sounds strange after explaining that there are several
  Perl 6 implementations. changed to 'Perl 6 compilers'

src/preface.pod

@@ -30,7 +30,7 @@ experience programming in another programming language. However, no
 prior knowledge of Perl is necessary. After working through this book, a
 programmer should have a solid grasp of the basics of Perl 6. That means
 that they should be able to solve their own problems with Perl 6. This
-book is not a comprehensive reference. It is a series of tutorials.
+book is not a comprehensive reference; it is a series of tutorials.
 
 =head1 Relationship between Perl 6 and Perl 5
 
@@ -99,7 +99,7 @@ to the Perl 6 community, there are more resources available to you:
 
 =item World Wide Web
 
-The Perl 6 homepage can be found at C<http://perl6.org/>. It contains pointers
+The Perl 6 homepage can be found at C<http://perl6.org> -- it contains pointers
 to many useful resources.
 
 =item IRC
@@ -112,8 +112,8 @@ If you need some programming help with Perl 6, send an email to
 C<perl6-users@perl.org>.
 
 For issues regarding the Perl 6 language specification you can contact
-C<perl6-language@perl.org>, for issues regarding the compiler send email to
-C<perl6-compiler@perl.org>
+C<perl6-language@perl.org>, for issues regarding Perl 6 compilers, send email
+to C<perl6-compiler@perl.org>
 
 =back