docs: update multi-module project instructions

Author: hugo-vrijswijk

README.md

@@ -32,7 +32,7 @@ After adding the plugin, Stryker4s can be used by running `sbt stryker` in the r
 
 ### Multi-module projects
 
-Multi-module projects are not yet fully supported. However, there is a workaround you can use while we work on a better solution. Set the base-directory to the correct directory of the submodule with the [`base-dir` configuration setting](https://stryker-mutator.io/docs/stryker4s/configuration/#base-dir-string). Then you can run `sbt "project yourSubmoduleNameHere" stryker` to set the active project and run Stryker4s.
+Multi-module projects are fully supported. Run Stryker on the desired module by running `sbt <module-name>/stryker`.
 
 ## Maven plugin
 

docs/getting-started.md

@@ -28,6 +28,12 @@ Run Stryker4s to mutation test your project:
 sbt stryker
 ```
 
+Or on multi-module projects:
+
+```shell
+sbt <module-name>/stryker
+```
+
 ## 4 Having trouble?
 
 Are you having troubles? Try enabling debug logging. For more information on how to enable debug logging visit our [configuration page](./configuration.md#log-level-string).