I don't feel terribly strongly either way, but I do lean towards the cleaner "Go" as that is the language's true name and is more idiomatic Go :)

Folks will surely understand what it means either way, but I figured we should try to get ourselves set off on the right foot!

For the record I think a mix of terms could work too. Like the community url could remain the same: /c/golang aka !golang but then the 'nice' name could just be "Go programming language" or the context could be understood as we are on programming.dev and it could just be "Go", as well as having the icon to help people identify it as the programming language.