Update website/content/docs/extending/custom-builders.mdx

Co-authored-by: Wilken Rivera <dev@wilkenrivera.com>

website/content/docs/extending/custom-builders.mdx

@@ -21,7 +21,8 @@ basics](/docs/extending/plugins).
 
 ~> **Warning!** This is an advanced topic. If you're new to Packer, we
 recommend getting comfortable with using Packer and its officially maintained
-plugins before before you dive into writing plugins of your own.
+plugins before you dive into writing plugins of your own.
+
 
 Custom plugins are written in [golang](https://golang.org/), so this guide
 assumes that you have some familiarity with that programming language.
@@ -305,4 +306,4 @@ order to make it available to the Packer core as a plugin. We have created a
 repo to give you an idea of the relationship between the builder
 implementation and the server implementation within a repository, and then read
 [basics of how Plugins work](/docs/extending/plugins), which breaks down all the
-server details.
+server details.