Merge branch '2.1.x'

Closes spring-projectsgh-17972

Author: snicoll

spring-boot-project/spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -937,7 +937,7 @@ following example:
 
 Logs are stored in a `logs` directory relative to the working directory of the
 application. You can customize this location by setting the
-`server.undertow.accesslog.directory` property.
+`server.undertow.accesslog.dir` property.
 
 Finally, access logging for Jetty can also be configured as follows: