Fix inconsistent devtools doc

[quaff]

DevTools only log a message and doesn't set logging.level.web to DEBUG

spring-boot/spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/env/DevToolsPropertyDefaultsPostProcessor.java

Lines 90 to 94 in dc5acb0

	if (isWebApplication(environment) && !environment.containsProperty(WEB_LOGGING)) {
	logger.info(LogMessage.format(
	"For additional web related logging consider setting the '%s' property to 'DEBUG'",
	WEB_LOGGING));
	}