Hi,
First … please format your post.
If you dont know how … see here: [HowTo] Post command output and file content as formatted text
Does manjaro have that file?
I dont think so by default.
And it shouldnt. Beginning with systemd 207 onwards that file is no longer read for configurations.
For changes you should probably use a different file - something like /etc/sysctl.d/99-mystuff.conf or similar. Just as mentioned in the file you referenced.
(example … I have /etc/sysctl.d/99-vm-zram-parameters.conf)
To see a lot more about it: