docs: Use <Hn> as Heading elements instead of <DIV class="doc_foo">.

H1 ... doc_title
H2 ... doc_section
H3 ... doc_subsection
H4 ... doc_subsubsection

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129736 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/tutorial/LangImpl3.html b/docs/tutorial/LangImpl3.html
index 42e5169..468a1bf 100644
--- a/docs/tutorial/LangImpl3.html
+++ b/docs/tutorial/LangImpl3.html
@@ -11,7 +11,7 @@
 
 <body>
 
-<div class="doc_title">Kaleidoscope: Code generation to LLVM IR</div>
+<h1>Kaleidoscope: Code generation to LLVM IR</h1>
 
 <ul>
 <li><a href="index.html">Up to Tutorial Index</a></li>
@@ -34,7 +34,7 @@
 </div>
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="intro">Chapter 3 Introduction</a></div>
+<h2><a name="intro">Chapter 3 Introduction</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">
@@ -57,7 +57,7 @@
 </div>
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="basics">Code Generation Setup</a></div>
+<h2><a name="basics">Code Generation Setup</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">
@@ -147,7 +147,7 @@
 </div>
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="exprs">Expression Code Generation</a></div>
+<h2><a name="exprs">Expression Code Generation</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">
@@ -293,7 +293,7 @@
 </div>
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="funcs">Function Code Generation</a></div>
+<h2><a name="funcs">Function Code Generation</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">
@@ -515,8 +515,7 @@
 </div>
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="driver">Driver Changes and 
-Closing Thoughts</a></div>
+<h2><a name="driver">Driver Changes and Closing Thoughts</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">
@@ -657,7 +656,7 @@
 
 
 <!-- *********************************************************************** -->
-<div class="doc_section"><a name="code">Full Code Listing</a></div>
+<h2><a name="code">Full Code Listing</a></h2>
 <!-- *********************************************************************** -->
 
 <div class="doc_text">