Polish

See gh-13148

spring-boot-project/spring-boot-tools/spring-boot-configuration-metadata/src/main/java/org/springframework/boot/configurationmetadata/SentenceExtractor.java

@@ -17,7 +17,9 @@
 package org.springframework.boot.configurationmetadata;
 
 import java.text.BreakIterator;
+import java.util.Arrays;
 import java.util.Locale;
+import java.util.stream.Collectors;
 
 /**
  * Utility to extract the first sentence of a text.
@@ -45,11 +47,7 @@ class SentenceExtractor {
 
 	private String removeSpaceBetweenLine(String text) {
 		String[] lines = text.split(System.lineSeparator());
-		StringBuilder sb = new StringBuilder();
-		for (String line : lines) {
-			sb.append(line.trim()).append(" ");
-		}
-		return sb.toString().trim();
+		return Arrays.stream(lines).map(String::trim).collect(Collectors.joining(" "));
 	}
 
 }