doc/manual: indent the CVE example the same as the CVE list item

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

docs/manual/adding-packages-generic.adoc

@@ -503,7 +503,7 @@ not and can not work as people would expect it should:
   the package, or when the CVE for some reason does not affect the
   Buildroot package. A Makefile comment must always precede the
   addition of a CVE to this variable. Example:
-
++
 ----------------------
 # 0001-fix-cve-2020-12345.patch
 LIBFOO_IGNORE_CVES += CVE-2020-12345