manual: don't use a comment at the end of the version variable assignment

The comment at the end of the version string assigment could lead to a download
failure so don't use it as a example.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Reported-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

docs/manual/adding-packages-tips.txt

@@ -42,7 +42,8 @@ on GitHub. As GitHub is known to have changed download mechanisms in the
 past, the 'github' helper function should be used as shown below.
 
 ------------------------
-FOO_VERSION = v1.0 # tag or full commit ID
+# Use a tag or a full commit ID
+FOO_VERSION = v1.0
 FOO_SITE = $(call github,<user>,<package>,$(FOO_VERSION))
 ------------------------