Yesterday the future function Siri Shortcuts was presented at WWDC18.
Unfortunately, as is often the case, this workflow option has been implemented on the new macOS Mojave I've forgotten again 
But that doesn't matter to us KM users, as we can already use „Siri shortcuts“ on the Mac with KM.
Simply create a macro with a shortcut as trigger and then store it as voice command in the system settings under help - dictation... voila
A few examples here in the Twitter Post: