Make section IDs in GEOM chapter lowercase, and adjust references to them

from other parts of the book.

en_US.ISO8859-1/books/handbook/geom/chapter.xml

@@ -5,7 +5,7 @@
 
 -->
 
-<chapter id="GEOM">
+<chapter id="geom">
   <chapterinfo>
     <authorgroup>
       <author>
@@ -18,7 +18,7 @@
 
   <title>GEOM: Modular Disk Transformation Framework</title>
 
-  <sect1 id="GEOM-synopsis">
+  <sect1 id="geom-synopsis">
     <title>Synopsis</title>
 
     <indexterm>
@@ -81,7 +81,7 @@
     </itemizedlist>
   </sect1>
 
-  <sect1 id="GEOM-intro">
+  <sect1 id="geom-intro">
     <title>GEOM Introduction</title>
 
     <para>GEOM permits access and control to classes, such as Master
@@ -93,7 +93,7 @@
       operating system utilities.</para>
   </sect1>
 
-  <sect1 id="GEOM-striping">
+  <sect1 id="geom-striping">
     <sect1info>
       <authorgroup>
 	<author>
@@ -224,7 +224,7 @@ Done.</screen>
     <screen>&prompt.root; <userinput>echo 'geom_stripe_load="YES"' &gt;&gt; /boot/loader.conf</userinput></screen>
   </sect1>
 
-  <sect1 id="GEOM-mirror">
+  <sect1 id="geom-mirror">
     <title>RAID1 - Mirroring</title>
 
     <indexterm>
@@ -269,7 +269,7 @@ Done.</screen>
 	first.</para>
     </warning>
 
-    <sect2 id="GEOM-mirror-metadata">
+    <sect2 id="geom-mirror-metadata">
       <title>Metadata Issues</title>
 
       <para>Many disk systems store metadata at the end of each disk.
@@ -305,7 +305,7 @@ Done.</screen>
 	the disk and does not conflict with &man.gmirror.8;.</para>
     </sect2>
 
-    <sect2 id="GEOM-mirror-two-new-disks">
+    <sect2 id="geom-mirror-two-new-disks">
       <title>Creating a Mirror with Two New Disks</title>
 
       <para>In this example, &os; has already been installed on a
@@ -428,7 +428,7 @@ Done.</screen>
 	single drive.</para>
     </sect2>
 
-    <sect2 id="GEOM-mirror-existing-drive">
+    <sect2 id="geom-mirror-existing-drive">
       <title>Creating a Mirror with an Existing Drive</title>
 
       <para>In this example, &os; has already been installed on a
@@ -802,7 +802,7 @@ mountroot&gt;</screen>
       <screen>&prompt.root; <userinput>gmirror forget gm0</userinput></screen>
 
       <para>Any old metadata should be <link
-	  linkend="GEOM-mirror-metadata">cleared from the replacement
+	  linkend="geom-mirror-metadata">cleared from the replacement
 	  disk</link>.  Then the disk, <devicename>ada4</devicename>
 	for this example, is inserted into the mirror:</para>
 
@@ -824,7 +824,7 @@ mountroot&gt;</screen>
     </sect2>
   </sect1>
 
-  <sect1 id="GEOM-raid3">
+  <sect1 id="geom-raid3">
     <sect1info>
       <authorgroup>
 	<author>

en_US.ISO8859-1/books/handbook/preface/preface.xml

@@ -477,7 +477,7 @@
       </listitem>
     </varlistentry>
     <varlistentry>
-      <term><emphasis><xref linkend="GEOM-synopsis"/>,
+      <term><emphasis><xref linkend="geom-synopsis"/>,
 	GEOM</emphasis></term>
       <listitem>
 	<para>Describes what the GEOM framework in &os; is and how

en_US.ISO8859-1/books/handbook/vinum/chapter.xml

@@ -54,7 +54,7 @@
     <note>
       <para>Starting with &os;&nbsp;5, <devicename>vinum</devicename>
 	has been rewritten in order to fit into the <link
-	  linkend="GEOM">GEOM architecture</link>, while retaining the
+	  linkend="geom">GEOM architecture</link>, while retaining the
 	original ideas, terminology, and on-disk metadata.  This
 	rewrite is called <emphasis>gvinum</emphasis> (for <emphasis>
 	  GEOM vinum</emphasis>).  While this chapter uses the term