chore: reword

Co-authored-by: Sridhar Ratnakumar <[email protected]>

doc/custom-service.md

@@ -2,7 +2,7 @@
 
 When using `services-flake` you are not just limited to the [[services|builtin services]]. You can also define your own service.
 
-By default, the services provided in `services-flake` support multiple instances, allowing you to run several instances of the same service simultaneously. However, you also have the option to create custom single-instance services. In the following sections, we’ll explore how to define custom services of both types.
+By default, `services-flake` supports multiple instances for each service, allowing you to run several instances of the same service simultaneously. However, you also have the option to create custom single-instance services. In the following sections, we’ll explore how to define custom services of both types.
 
 {#single-instance}
 ## Single instance service