Update book2.html

Author: murphyk

book2.html

@@ -20,12 +20,12 @@ <h2>Key links</h2>
 	    <li> <a href="https://github.com/probml/pml2-book/blob/main/toc2-long-2023-01-19.pdf">
 		    Long table of  contents</a>
 
-<li> <a href="https://github.com/probml/pml2-book/blob/main/preface2-2023-01-02.pdf">Preface</a>.
+<li> <a href="https://github.com/probml/pml2-book/blob/main/preface2-2023-01-02.pdf">Preface</a>
 
   <li> <a href="https://github.com/probml/pml2-book/releases/latest/download/book2.pdf">
     Draft pdf of the main book</a>, 2023-01-19.  CC-BY-NC-ND license. (Please cite the official reference below.)
 
-<li> <a href="https://github.com/probml/pml-book/blob/main/supp2.md">Supplementary material</a>..
+<li> <a href="https://github.com/probml/pml-book/blob/main/supp2.md">Supplementary material</a>
 
   <li> <a href="https://github.com/probml/pml2-book/issues">Issue tracker</a>.