update renderer plugin docs usage clarifications

Author: thescientist13

src/pages/docs/reference/plugins-api.md

@@ -380,9 +380,9 @@ This plugin type supports the following options:
 
 ### Examples
 
-#### Default
+#### Execute Route Module
 
-The recommended Greenwood API for executing server rendered code is in a function that is expected to implement any combination of [these APIs](/docs/pages/server-rendering/#api); `default export`, `getBody`, `getLayout`, and `getFrontmatter`.
+The recommended Greenwood API for executing server rendered code is in a function that is expected to implement any combination of [these APIs](/docs/pages/server-rendering/#api); `default export`, `getBody`, `getLayout`, and `getFrontmatter`. For efficient SSR, `contentOptions` are provided to signal to the implementation which content is being requested (one of frontmatter, body, or layout contents).
 
 You can follow the [WCC default implementation for Greenwood](https://github.com/ProjectEvergreen/greenwood/blob/master/packages/cli/src/lib/execute-route-module.js) as a reference.