Add PDF download link in html only

Close #64

html.cfg

@@ -45,5 +45,15 @@
     user-select: none;
 }}
 
+\Css{.flushright:first-child {
+    position:absolute;
+    top: 10px;
+    right: 50px;
+}}
+
 \begin{document}
 \EndPreamble
+
+\begin{flushright}
+\href{https://github.com/sysprog21/lkmpg/releases/download/latest/lkmpg.pdf}{Download PDF document}
+\end{flushright}