[docs] Update HTML pages to refer to CSS in a way that works locally and with Sphinx.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155153 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/HowToSubmitABug.html b/docs/HowToSubmitABug.html
index baefce3..6004bec 100644
--- a/docs/HowToSubmitABug.html
+++ b/docs/HowToSubmitABug.html
@@ -4,7 +4,7 @@
 <head>
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
   <title>How to submit an LLVM bug report</title>
-  <link rel="stylesheet" href="llvm.css" type="text/css">
+  <link rel="stylesheet" href="_static/llvm.css" type="text/css">
 </head>
 <body>