docs: prefer lowercase html tags

Signed-off-by: Brian Paul <brianp@vmware.com>
diff --git a/docs/intro.html b/docs/intro.html
index f4e0f01..ef04f35 100644
--- a/docs/intro.html
+++ b/docs/intro.html
@@ -31,7 +31,7 @@
 
 
 
-<H1>Project History</H1>
+<h1>Project History</h1>
 
 <p>
 The Mesa project was originally started by Brian Paul.
@@ -157,7 +157,7 @@
 
 
 
-<H1>Major Versions</H1>
+<h1>Major Versions</h1>
 
 <p>
 This is a summary of the major versions of Mesa.
@@ -166,7 +166,7 @@
 </p>
 
 
-<H2>Version 8.x features</H2>
+<h2>Version 8.x features</h2>
 <p>
 Version 8.x of Mesa implements the OpenGL 3.0 API.
 The developers at Intel deserve a lot of credit for implementing most
@@ -175,14 +175,14 @@
 </p>
 
 
-<H2>Version 7.x features</H2>
+<h2>Version 7.x features</h2>
 <p>
 Version 7.x of Mesa implements the OpenGL 2.1 API.  The main feature
 of OpenGL 2.x is the OpenGL Shading Language.
 </p>
 
 
-<H2>Version 6.x features</H2>
+<h2>Version 6.x features</h2>
 <p>
 Version 6.x of Mesa implements the OpenGL 1.5 API with the following
 extensions incorporated as standard features:
@@ -222,7 +222,7 @@
 
 
 
-<H2>Version 5.x features</H2>
+<h2>Version 5.x features</h2>
 <p>
 Version 5.x of Mesa implements the OpenGL 1.4 API with the following
 extensions incorporated as standard features:
@@ -248,7 +248,7 @@
 </ul>
 
 
-<H2>Version 4.x features</H2>
+<h2>Version 4.x features</h2>
 
 <p>
 Version 4.x of Mesa implements the OpenGL 1.3 API with the following
@@ -267,7 +267,7 @@
 <li>GL_ARB_transpose_matrix
 </ul>
 
-<H2>Version 3.x features</H2>
+<h2>Version 3.x features</h2>
 
 <p>
 Version 3.x of Mesa implements the OpenGL 1.2 API with the following
@@ -283,7 +283,7 @@
 </ul>
 
 
-<H2>Version 2.x features</H2>
+<h2>Version 2.x features</h2>
 <p>
 Version 2.x of Mesa implements the OpenGL 1.1 API with the following
 features.