Update docs

README.md

@@ -28,10 +28,10 @@ itself.
 - ESM and CommonJS support
 - Support for copying binary files as well as rendering template files
 - Variable substitution in file names
-- Use EJS (default) or any other template engine
-- Overridable file system methods. You can override the default functions used
+- Use EJS (by default) or [any other template engine][2]
+- Overridable file system methods. You can [override][3] the default functions used
   to create directories, read files, write files, and copy files. That is
-  useful for testing, logging, implementing interactive prompts, etc.
+  useful for [testing][1], logging, implementing interactive prompts, etc.
 
 ## Installation
 
@@ -143,3 +143,7 @@ await fileGenerator.generate(
   variables,
 );
 ```
+
+[1]: ./src/index.test.ts
+[2]: #custom-template-engine
+[3]: #custom-file-system-functions