Change HelloWorld.module.scss to HelloWorldFieldCustomizer.module.scss

Please Change HelloWorld.module.scss to HelloWorldFieldCustomizer.module.scss - this is probably a copy/paste artefact.

Author: PiotrekKrakowiak

docs/spfx/extensions/get-started/building-simple-field-customizer.md

@@ -213,7 +213,7 @@ You cannot currently use the local Workbench to test SharePoint Framework Extens
 
 Now that we have successfully tested the out-of-the-box starting point of the Field Customizer, let's modify the logic slightly to have a more polished rendering of the field value.
 
-1. Open the **HelloWorld.module.scss** file in the **src\extensions\helloWorld** folder, and update the styling definition as follows.
+1. Open the **HelloWorldFieldCustomizer.module.scss** file in the **src\extensions\helloWorld** folder, and update the styling definition as follows.
 
     ```
     .HelloWorld {