You would need a little bit of text mode. I would start by selecting the Document Version > File Name, because you can repurpose a lot of the code. Once you select it, switch over to text mode (click on text mode in the upper right corner) and then everywhere that you see the word "fileName", replace it with "document:name" instead. You should end up with something like this:
group.0.linkedname=documentVersion
group.0.namekey=view.relatedcolumn
group.0.namekeyargkey.0=documentVersion
group.0.namekeyargkey.1=document:name
group.0.valuefield=documentVersion:document:name
group.0.valueformat=string
textmode=true
On top of this, I would suggest adding one more line:
group.0.displayname=Document Name
(that's just because I like my grouping name to be a bit tidier than what I would otherwise get.)