Escape reserved asciidoc character in generated documentation

See gh-17663

spring-boot-project/spring-boot-tools/spring-boot-configuration-docs/src/main/java/org/springframework/boot/configurationdocs/SingleConfigurationTableEntry.java

@@ -76,7 +76,7 @@ class SingleConfigurationTableEntry extends ConfigurationTableEntry {
 			builder.append("|");
 		}
 		else {
-			builder.append("|+++", this.description, "+++");
+			builder.append("|+++", this.description.replace("|", "\\|"), "+++");
 		}
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-configuration-docs/src/test/java/org/springframework/boot/configurationdocs/SingleConfigurationTableEntryTests.java

@@ -86,6 +86,20 @@ class SingleConfigurationTableEntryTests {
 				+ "|+++This is a description.+++" + NEWLINE);
 	}
 
+	@Test
+	void descriptionWithPipe() {
+		ConfigurationMetadataProperty property = new ConfigurationMetadataProperty();
+		property.setId("spring.test.prop");
+		property.setDefaultValue("first\\second");
+		property.setDescription("This is a description with a | pipe.");
+		property.setType("java.lang.String");
+		SingleConfigurationTableEntry entry = new SingleConfigurationTableEntry(property);
+		AsciidocBuilder builder = new AsciidocBuilder();
+		entry.write(builder);
+		assertThat(builder.toString()).isEqualTo("|`+spring.test.prop+`" + NEWLINE + "|`+first\\\\second+`" + NEWLINE
+				+ "|+++This is a description with a \\| pipe.+++" + NEWLINE);
+	}
+
 	@Test
 	void mapProperty() {
 		ConfigurationMetadataProperty property = new ConfigurationMetadataProperty();