How do I use a custom emoji (and key)?

So [on the website](https://allcontributors.org/docs/en/bot/configuration#:~:text=%22types%22%3A%20%7B%0A%20%20%20%20%22custom%22%3A%20%7B%0A%20%20%20%20%20%20%22symbol%22%3A%20%22%F0%9F%94%AD%22%2C%0A%20%20%20%20%20%20%22description%22%3A%20%22A%20custom%20contribution%20type.%22%2C%0A%20%20%20%20%20%20%22link%22%3A%20%22%5B%3C%25%3D%20symbol%20%25%3E%5D(%3C%25%3D%20url%20%25%3E%20%5C%22%3C%25%3D%20description%20%25%3E%5C%22)%2C%22%0A%20%20%20%20%7D%0A%20%20%7D%2C) it says at the bottom that one can use custom emojis in the `.all-contributorsrc` file. It instructs you to do the following:

```json
"types": {
"custom": {
"symbol": "🔭",
"description": "A custom contribution type.",
"link": "[<%= symbol %>](<%= url %> \"<%= description %>\"),"
}
},
```

Now that this has been created, how would I go about adding this emoji to someone? Is the emoji key `custom`? Because I tried these commands and none of them were recognized:
```
@all-contributors add @user for custom
@all-contributors add @user for A custom contribution type
@all-contributors add @user for 🔭
```
and none worked. Could someone instruct me on how to do this? (Also maybe update those docs!)