Polish asciidoctor formatting

spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc

@@ -8901,14 +8901,12 @@ Disable launch script configuration when building a jar file that is intended to
 
 Here’s how you can launch your jar with a `layertools` jar mode:
 
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 $ java -Djarmode=layertools -jar my-app.jar
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 This will provide the following output:
 
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 Usage:
   java -Djarmode=layertools -jar my-app.jar
@@ -8922,7 +8920,6 @@ Available commands:
 The `extract` command can be used to easily split the application into layers to be added to the dockerfile.
 Here's an example of a Dockerfile using `jarmode`.
 
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 FROM adoptopenjdk:11-jre-hotspot as builder
 WORKDIR application