with hugo v0.150, you can do:

{{ $url := printf "%s%s%s" $Site.Params.contentCommitsURL (replace $File.Dir "\\" "/")  $File.LogicalName }}

Like say in hugo doc: printf FORMAT [INPUT]
You could use:

{{ printf "%s %s %s" $varA $varB $VarC }}

format %s is for string
other format could be find in go doc