docs: improve importSource docs

Author: Rel1cx

website/pages/docs/configuration.mdx

@@ -8,9 +8,9 @@ This plugin provides the following configurations:
 
 ### `importSource`
 
-(type: `string, default: `"react"`)
+(type: `string`, default: `"react"`)
 
-The identifier that's used for React import detection.
+The source where React is imported from.\
 This allows to specify a custom import location for React when not using the official distribution (e.g. `@pika/react`, etc).
 
 ### `jsxPragma`