Merge pull request #979 from pmcelhaney/usage-guide-fixes.md

fixes and enhancements to the usage documentation

docs/usage-without-openapi.md

@@ -2,9 +2,9 @@
 
 ## Running the server
 
-If you don't have an OpenAPI document, you can still use Counterfact. You just won't have the benefit of code generation and you'll have to write your mocks by hand.
+If you don't have an [OpenAPI document](https://swagger.io/specification/), you can still use Counterfact. You won't have the benefit of code generation and autocomplete in your IDE, but you can still use the API to write JavaScript code that is terse and intuitive.
 
-If you run Counterfact without any arguments, it will run in "OpenAPI-free" mode.
+If you run Counterfact without any arguments, it will run in "OpenAPI-free" mode. (Technically, under the covers, it uses an empty OpenAPI document.)
 
 ```sh
 npx counterfact
@@ -40,6 +40,6 @@ For more information on the `$` object, see the [usage guide](./usage.md).
 
 ## Now that you know how to work without an OpenAPI doc, here's why you should have one anyway
 
-OpenAPI is the de-facto standard for documenting REST APIs. Counterfact is just one of dozens of tools that use it. And if you pass Counterfact an OpenAPI doc, it will save you a lot of time by automatically generating default type-safe implementations of each API, with powerful context-sensitive autocomplete when you want to make changes.
+OpenAPI is the de-facto standard for documenting REST APIs. Counterfact is just one of [hundreds of tools](https://openapi.tools/) that use it. And if you pass Counterfact an OpenAPI doc, it will save you a lot of time by automatically generating default type-safe implementations of each API, with powerful context-sensitive autocomplete when you want to make changes.
 
 Not many people love writing documentation. Fewer people still love working on APIs that are not documented. Counterfact makes documentation useful, with immediate ROI, so that so that maintaining the docs is just as rewarding as writing code.