That is what the documentation you are referring to mentions.
Set up access to multiple repositories
To create an SSH key for each of your repositories, follow the steps outlined above.
After you have added the keys to the remote repositories, create a local ~/.ssh/config file to alias each of the keys to their corresponding repository names.
For example, if you have two repos configured on GitHub, testing and testing2, and both your cPanel and GitHub usernames are cptest, create or modify the ~/.ssh/config file with these contents:
Host testing.github.com
Hostname github.com
IdentityFile /home/cptest/.ssh/testing
User git
Host testing2.github.com
Hostname github.com
IdentityFile /home/cptest/.ssh/testing2
User git
Compared to their documentation, I would use:
IdentityFile /home/cptest/... (instead of IdentityFile=...)
User git
a FQDN-like Host entry: xxx.yyy.com
That way, the URL becomes: git clone testing.github.com:me/myRepo
If the cPanel requires a valid protocol, use:
ssh://github.com-testing/me/myRepo
^^^^^^ ^^^
(valid protocol) (/, not 
In your case:
ssh://top25vineyards.github.com/me/myRepo
ssh://top25vineyards.github.com/Penk13/top25vineyards
(to mimic an fully-qualified domain name)