Use parenthesis with single-arg lambdas

Use regular expression search/replace to ensure all single-arg
lambdas have parenthesis. This aligns with the style used in Spring
Boot and ensure that single-arg and multi-arg lambdas are consistent.

Issue gh-8945

samples/boot/hellowebflux-method/src/main/java/sample/SecurityConfig.java

@@ -40,7 +40,7 @@ public class SecurityConfig {
 		return http
 			// Demonstrate that method security works
 			// Best practice to use both for defense in depth
-			.authorizeExchange(exchanges -> exchanges
+			.authorizeExchange((exchanges) -> exchanges
 				.anyExchange().permitAll()
 			)
 			.httpBasic(withDefaults())