Install: ch03: Consistently name subsections of Preparing

src/install/3_beginning.xml

@@ -14,7 +14,7 @@
         </itemizedlist>
         <para>Once you have these items collected, you will be ready to install Adélie Linux on your computer.</para>
         <section id="prep_backup">
-            <title>Data Backup</title>
+            <title>Backup Data</title>
             <para>If your computer has an existing operating environment, you must backup your data before starting Adélie Linux System Installation.
                 This ensures that you will have a copy of your data in case of a system error during installation.
                 For more information on how to backup your data, consult your current operating environment's documentation.
@@ -35,7 +35,7 @@
                 You will also need additional room on your disk for your personal data files.</para>
         </section>
         <section id="prep_naming">
-            <title>Naming Your Computer</title>
+            <title>Name Your Computer</title>
             <para>What's in a name?  A lot, when you're choosing the name of your computer.
                 Your computer's name will be shown on the login screen, in the application launcher, and on the command prompt.
                 It will additionally identify it to others if you have a home or organisational network.