Update plugins.md

Changes "Explorer" to a hyperlink to the explorer documentation. This is important for those unfamiliar with Roblox terminology or who do not know what the Explorer looks like.

Author: sirnolag

content/en-us/studio/plugins.md

@@ -138,7 +138,7 @@ The only way to distribute and set a price for a plugin is through the Creator D
 
 To distribute a plugin:
 
-1. In the **Explorer** window, right-click a plugin script, then select **Publish as Plugin** from the contextual menu.
+1. In the [**Explorer**](../studio/explorer.md) window, right-click a plugin script, then select **Publish as Plugin** from the contextual menu.
 1. **(Optional)** In the upper-left corner of the asset configuration window, click the image to upload a 512×512 image.
 1. Fill in the following fields: