Update sources.md

hi team, link is currently broken for source configurations.  when you click on the current link it brings you to (https://docs.getdbt.com/docs/build/reference/source-configs) instead of (https://docs.getdbt.com/reference/source-configs)

I think all that's missing is a `/`?

website/docs/docs/build/sources.md

@@ -8,7 +8,7 @@ search_weight: "heavy"
 
 ## Related reference docs
 * [Source properties](/reference/source-properties)
-* [Source configurations](reference/source-configs)
+* [Source configurations](/reference/source-configs)
 * [`{{ source() }}` jinja function](/reference/dbt-jinja-functions/source)
 * [`source freshness` command](/reference/commands/source)