Link to the alias model configuration page (#5250)

[Preview](https://docs-getdbt-com-git-dbeatty10-patch-4-dbt-labs.vercel.app/docs/build/custom-aliases)

## What are you changing in this pull request and why?

It seems like the [custom
aliases](https://docs.getdbt.com/docs/build/custom-aliases) page should
link to the
[`alias`](https://docs.getdbt.com/reference/resource-configs/alias)
model configuration somewhere.

## Checklist
- [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.

website/docs/docs/build/custom-aliases.md

@@ -6,7 +6,7 @@ id: "custom-aliases"
 
 ## Overview
 
-When dbt runs a model, it will generally create a relation (either a `table` or a `view`) in the database. By default, dbt uses the filename of the model as the identifier for this relation in the database. This identifier can optionally be overridden using the `alias` model configuration.
+When dbt runs a model, it will generally create a relation (either a `table` or a `view`) in the database. By default, dbt uses the filename of the model as the identifier for this relation in the database. This identifier can optionally be overridden using the [`alias`](/reference/resource-configs/alias) model configuration.
 
 ### Why alias model names?
 The names of schemas and tables are effectively the "user interface" of your <Term id="data-warehouse" />. Well-named schemas and tables can help provide clarity and direction for consumers of this data. In combination with [custom schemas](/docs/build/custom-schemas), model aliasing is a powerful mechanism for designing your warehouse.