Add a missing backslash

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11598 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/check.xml

@@ -42,7 +42,7 @@
 
     <para>Prepare Check for compilation:</para>
 
-<screen><userinput remap="configure">./configure --prefix=/usr
+<screen><userinput remap="configure">./configure --prefix=/usr \
             --docdir=/usr/share/doc/check-&check-version;</userinput></screen>
 
     <para>Build the package:</para>