Update readme (#221)

* Update intro text

Avoid referring to "Procfile application" as mentioned here #217 (comment)

* Remove yaml reference

There isn't really a need for a link here (as the immediately preceding section links to the Procfile docs), but including it anyway. Also see #217 (comment)

README.md

@@ -5,7 +5,7 @@
 
 
 `heroku/procfile` is the [Heroku Cloud Native Buildpack][heroku-buildpacks]
-for Procfile applications. It replicates the behavior of [`Procfile`](https://devcenter.heroku.com/articles/procfile)
+for applications that use a Procfile to declare process types. It replicates the behavior of [`Procfile`](https://devcenter.heroku.com/articles/procfile)
 from builds on the Heroku Platform.
 
 > [!IMPORTANT]
@@ -35,8 +35,7 @@ to exist in the root project directory.
 
 ## Configuration
 
-You may configure which processes are included in a build result by using a
-YAML-like syntax with bash commands:
+You may configure which process types and commands are included in a build result [like this](https://devcenter.heroku.com/articles/procfile#procfile-format):
 
 ```yaml
 # Example Procfile