Fix code examples in documentation

The changed code examples in this commit used the
`.end()` method which does not exist in `SimpleStepBuilder`.

Issue #3889

Author: LichKing-lee

spring-batch-docs/asciidoc/domain.adoc

@@ -77,7 +77,6 @@ public Job footballJob() {
                      .start(playerLoad())
                      .next(gameLoad())
                      .next(playerSummarization())
-                     .end()
                      .build();
 }
 ----
@@ -113,7 +112,6 @@ public Job footballJob() {
                      .start(playerLoad())
                      .next(gameLoad())
                      .next(playerSummarization())
-                     .end()
                      .build();
 }
 ----

spring-batch-docs/asciidoc/job.adoc

@@ -41,7 +41,6 @@ public Job footballJob() {
                      .start(playerLoad())
                      .next(gameLoad())
                      .next(playerSummarization())
-                     .end()
                      .build();
 }
 ----
@@ -106,7 +105,6 @@ public Job footballJob() {
                      .start(playerLoad())
                      .next(gameLoad())
                      .next(playerSummarization())
-                     .end()
                      .build();
 }
 ----

spring-batch-docs/asciidoc/step.adoc

@@ -352,7 +352,6 @@ value of 10 as it would be defined in Java:
 public Job sampleJob() {
     return this.jobBuilderFactory.get("sampleJob")
                      .start(step1())
-                     .end()
                      .build();
 }
 
@@ -507,7 +506,6 @@ public Job footballJob() {
 				.start(playerLoad())
 				.next(gameLoad())
 				.next(playerSummarization())
-				.end()
 				.build();
 }