Merge previously split strings

Merge some string lines that were previously split because of the
90 chars wide formatting.

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/DependencyManagementPluginActionIntegrationTests.java

@@ -64,7 +64,7 @@ public class DependencyManagementPluginActionIntegrationTests {
 		assertThat(output).contains("During the build, one or more dependencies that "
 				+ "were declared without a version failed to resolve:");
 		assertThat(output).contains("org.springframework.boot:spring-boot-starter-web:");
-		assertThat(output).contains("Did you forget to apply the " + "io.spring.dependency-management plugin to the "
+		assertThat(output).contains("Did you forget to apply the io.spring.dependency-management plugin to the "
 				+ this.gradleBuild.getProjectDir().getName() + " project?");
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/SpringBootPluginIntegrationTests.java

@@ -42,7 +42,7 @@ class SpringBootPluginIntegrationTests {
 	void failFastWithVersionOfGradleLowerThanRequired() {
 		BuildResult result = this.gradleBuild.gradleVersion("4.9").buildAndFail();
 		assertThat(result.getOutput())
-				.contains("Spring Boot plugin requires Gradle 4.10" + " or later. The current version is Gradle 4.9");
+				.contains("Spring Boot plugin requires Gradle 4.10 or later. The current version is Gradle 4.9");
 	}
 
 	@Test