Add DTD information.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@52511 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/www/StaticAnalysisUsage.html b/www/StaticAnalysisUsage.html
index 7faa59f..204d755 100644
--- a/www/StaticAnalysisUsage.html
+++ b/www/StaticAnalysisUsage.html
@@ -1,3 +1,5 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+          "http://www.w3.org/TR/html4/strict.dtd">
 <html>
 <head>
   <title>Information on using the Static Analyzer ("Clang Checker")</title>