Discord just released a new feature that allows you to mention slash commands, the same way you mention people or channels. Here's how you do it.
Type the command and copy the ID
Type the command, without any parameters, and right click where my mouse is to copy the ID.
If there is no Copy ID button when you right click, you need to enable developer mode in Discord settings, the same setting required for copying all other types of IDs. Google will help.
Mention the command
The syntax for mentioning the command is as follows.
The second message shows the result.
You can also use any command name and any number for the command ID to make a fake command, but it won't be clickable: