fix wrong document code examples

Author: jiacheo

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/etl-pipeline.adoc

@@ -170,10 +170,10 @@ Example:
 public class MyTikaDocumentReader {
 
     @Value("classpath:/word-sample.docx") // This is the word document to load
-	private Resource resource;
+    private Resource resource;
 
-	List<Document> loadText() {
-        TikaDocumentReader tikaDocumentReader = new TikaDocumentReader(resourceUri);
+    List<Document> loadText() {
+        TikaDocumentReader tikaDocumentReader = new TikaDocumentReader(resource);
         return tikaDocumentReader.get();
     }
 }
@@ -229,4 +229,4 @@ See xref:api/vectordbs.adoc[Vector DB Documentation] for a full listing.
 The following class diagram illustrates the ETL interfaces and implementations.
 
 // image::etl-class-diagram.jpg[align="center", width="800px"]
-image::etl-class-diagram.jpg[align="center"]
+image::etl-class-diagram.jpg[align="center"]