manual: Add singular example for dependency comment

The manual always uses the format with multiple dependencies. This only
add an example where is a single dependency to show that this format is
applicable regardless of the number of dependencies.

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Acked-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

docs/manual/adding-packages-directory.txt

@@ -202,6 +202,10 @@ for example:
 --------------------------
 aircrack-ng needs a toolchain w/ largefile, threads
 --------------------------
+or
+--------------------------
+crda needs a toolchain w/ threads
+--------------------------
 
 Note that this text is kept brief on purpose, so that it will fit on a
 80-character terminal.