Documentation: Remove XHTML spec and fix errors (#1547)

* Documentation: Remove XHTML spec and fix errors
None of the docs follow the XHTML specification, which means
that programs that expect this (such as Gnome Web) as it is advertised
as such, will completely fail to parse it as it is incorrect syntax. So
it is removed.

* Remove .chm files

doc/html/zh-cn/EMV Smart Cards.html

@@ -1,5 +1,5 @@
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-CN" lang="zh-CN">
+<!DOCTYPE html>
+<html lang="zh-CN">
   <head>
     <meta http-equiv="content-type" content="text/html; charset=utf-8" />
     <title>
@@ -64,7 +64,7 @@
         <p>
           如需更多技术信息，请参阅 <a
             href="Keyfiles%20in%20VeraCrypt.html"
-            style="text-align: left; color: #0080c0; text-decoration: none.html"
+            style="text-align: left; color: #0080c0; text-decoration: none"
           >
             <em style="text-align: left">密钥文件</em></a> 章节中的 <em style="text-align: left">EMV智能卡</em> 部分。
         </p>