Add emoji to ingredient/cookware

Add emoji to the front of each ingredient depending on ingredient type.

This may be specified in the `.cookdocs.yaml` config file.

```yaml
...
emoji:
  ingredients:
    - herb:
        - cilantro
  cookware:
    - bowl_with_spoon:
        - bowl
...
```

```markdown
....
## Ingredients

- :herb: 1 Tbsp cilantro

## Cookware

- :bowl_with_spoon: 1 bowl
...
```