Simplify regex expressions

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/DurationStyle.java

@@ -36,7 +36,7 @@ public enum DurationStyle {
 	/**
 	 * Simple formatting, for example '1s'.
 	 */
-	SIMPLE("^([\\+\\-]?\\d+)([a-zA-Z]{0,2})$") {
+	SIMPLE("^([+-]?\\d+)([a-zA-Z]{0,2})$") {
 
 		@Override
 		public Duration parse(String value, ChronoUnit unit) {
@@ -62,7 +62,7 @@ public String print(Duration value, ChronoUnit unit) {
 	/**
 	 * ISO-8601 formatting.
 	 */
-	ISO8601("^[\\+\\-]?P.*$") {
+	ISO8601("^[+-]?P.*$") {
 
 		@Override
 		public Duration parse(String value, ChronoUnit unit) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/PeriodStyle.java

@@ -102,7 +102,7 @@ private void append(StringBuilder result, Period value, Unit unit) {
 	/**
 	 * ISO-8601 formatting.
 	 */
-	ISO8601("^[\\+\\-]?P.*$", 0) {
+	ISO8601("^[+-]?P.*$", 0) {
 
 		@Override
 		public Period parse(String value, ChronoUnit unit) {