Made Syslinux boot menu more useful

Added information on optional kernel arguments.

src/root/config/syslinux.cfg

@@ -26,7 +26,7 @@ LABEL liberte
     TEXT HELP
 Select for normal boot with modern video cards.
 In splash screen, press F2 for verbose mode.
-Disconnect boot media for emergency shutdown.
+Optional parameters: gentoo=i2p, gentoo=nosettings, cdroot=/dev/xxx
     ENDTEXT
 
 # nomodeset: KMS is incompatible with framebuffer
@@ -38,7 +38,7 @@ LABEL nokms
     TEXT HELP
 Select for normal boot with VESA framebuffer and no kernel mode-setting.
 In splash screen, press F2 for verbose mode.
-Disconnect boot media for emergency shutdown.
+Optional parameters: gentoo=i2p, gentoo=nosettings, cdroot=/dev/xxx
     ENDTEXT
 
 # nomodeset: KMS is problematic with console screen blanking