doc: various changes for validating HTML

(Fixes missing tags, extra tags, missing attributes, and such found by tidy -e)

R=golang-dev, adg1, adg
CC=golang-dev
https://golang.org/cl/2039043

doc/codereview_with_mq.html

@@ -36,11 +36,11 @@ prevent that case:
 <pre>
 [hooks]
 # Prevent "hg pull" if MQ patches are applied.
-prechangegroup.mq-no-pull = ! hg qtop > /dev/null 2>&1
+prechangegroup.mq-no-pull = ! hg qtop > /dev/null 2>&amp;1
 # Prevent "hg push" if MQ patches are applied.
-preoutgoing.mq-no-push = ! hg qtop > /dev/null 2>&1
+preoutgoing.mq-no-push = ! hg qtop > /dev/null 2>&amp;1
 # Prevent "hg update" if MQ patches are applied.
-preupdate.mq-no-update = ! hg qtop > /dev/null 2>&1
+preupdate.mq-no-update = ! hg qtop > /dev/null 2>&amp;1
 </pre>
 
 <h2>Making a change</h2>

doc/gccgo_install.html

@@ -396,9 +396,9 @@ This procedure is full of unstated caveats and restrictions and we make no
 guarantee that it will not change in the future. It is more useful as a
 starting point for real Go code than as a regular procedure.
 
-<h2 id="RTEMS Port">RTEMS Port</h2>
+<h2 id="RTEMS_Port">RTEMS Port</h2>
 <p>
-The <code>gccgo</code> compiler has been ported to <a href="http://www.rtems.com/"
+The <code>gccgo</code> compiler has been ported to <a href="http://www.rtems.com/">
 <code>RTEMS</code></a>. <code>RTEMS</code> is a real-time executive
 that provides a high performance environment for embedded applications
 on a range of processors and embedded hardware. The current <code>gccgo</code>

doc/go_for_cpp_programmers.html

@@ -198,7 +198,7 @@ the <code>else</code>, causing a syntax error.
 Since semicolons do end statements, you may continue using them as in
 C++.  However, that is not the recommended style.  Idiomatic Go code
 omits unnecessary semicolons, which in practice is all of them other
-than the initial <for> loop clause and cases where you want several
+than the initial <code>for</code> loop clause and cases where you want several
 short statements on a single line.
 
 <p>

doc/install.html

@@ -293,7 +293,6 @@ to override the defaults.
 	<code>386</code> (32-bit x86), and
 	<code>arm</code> (32-bit ARM, an incomplete port).
 	The valid combinations of <code>$GOOS</code> and <code>$GOARCH</code> are:
-	<p>
 	<table cellpadding="0">
 	<tr>
 	<th width="50"><th align="left" width="100"><code>$GOOS</code></th> <th align="left" width="100"><code>$GOARCH</code></th> <th align="left"></th>

doc/root.html

 <!-- The Go Programming Language -->
 
-<script>
+<script type="text/javascript">
   // On the frontpage we hide the header and navigation elements that other
   // pages have.
   document.getElementById('generatedHeader').style.display = 'none';