Scroll window to the top on render. (#423)

Wino.Mail/JS/reader.html

@@ -22,6 +22,7 @@
     <meta name="color-scheme" content="dark light">
     <script>
         function RenderHTML(htmlString) {
+            window.scroll(0, 0);
             var containerDiv = document.getElementById("readerDiv");
             containerDiv.innerHTML = htmlString;
         }