Update semantic-layer-6-advanced-metrics.md (#4789)

## What are you changing in this pull request and why?
Fix indent and incorrect filter and measure in `Ratio metrics` which are
causing errors in implementing the code:
```sql
 - name: food_revenue
    description: The revenue from food in each order.
    label: Food Revenue
    type: simple
    type_params:
      measure: revenue
      filter: |
        {{ Dimension('order__is_food_order') }} = true
```
to
```
 - name: food_revenue
   description: The revenue from food in each order.
   label: Food Revenue
   type: simple
   type_params:
     measure: food_revenue
```

## Checklist
<!--
Uncomment when publishing docs for a prerelease version of dbt:
- [ ] Add versioning components, as described in [Versioning
Docs](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#versioning-entire-pages)
- [ ] Add a note to the prerelease version [Migration
Guide](https://github.com/dbt-labs/docs.getdbt.com/tree/current/website/docs/docs/dbt-versions/core-upgrade)
-->
- [x] Review the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.
- [ ] For [docs
versioning](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#about-versioning),
review how to [version a whole
page](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#adding-a-new-version)
and [version a block of
content](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#versioning-blocks-of-content).
- [x] Add a checklist item for anything that needs to happen before this
PR is merged, such as "needs technical review" or "change base branch."

Author: mirnawong1

website/docs/best-practices/how-we-build-our-metrics/semantic-layer-6-advanced-metrics.md

@@ -21,13 +21,11 @@ We're not limited to just passing measures through to our metrics, we can also _
 
 ```YAML
  - name: food_revenue
-    description: The revenue from food in each order.
-    label: Food Revenue
-    type: simple
-    type_params:
-      measure: revenue
-      filter: |
-        {{ Dimension('order__is_food_order') }} = true
+   description: The revenue from food in each order.
+   label: Food Revenue
+   type: simple
+   type_params:
+     measure: food_revenue
 ```
 
 - 📝 Now we can set up our ratio metric.