Merge pull request rails#50340 from notapatch/pr-rails_on_rack_documentation

Update Rack::Head documentation to match code behavior [ci-skip]

Author: Edouard-chin

guides/source/configuring.md

@@ -840,7 +840,7 @@ Allows the method to be overridden if `params[:_method]` is set. This is the mid
 
 #### `Rack::Head`
 
-Converts HEAD requests to GET requests and serves them as so.
+Returns an empty body for all HEAD requests. It leaves all other requests unchanged.
 
 #### Adding Custom Middleware
 

guides/source/rails_on_rack.md

@@ -339,7 +339,7 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 **`Rack::Head`**
 
-* Converts HEAD requests to `GET` requests and serves them as so.
+* Returns an empty body for all HEAD requests. It leaves all other requests unchanged.
 
 **`Rack::ConditionalGet`**