Merge branch '2.1.x' into 2.2.x

Closes gh-21025

Author: philwebb

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

@@ -907,7 +907,13 @@ For example, to configure restart to always use a <<using-boot-devtools-restart-
 NOTE: If devtools configuration files are not found in `$HOME/.config/spring-boot`, the root of the `$HOME` folder is searched for the presence of a `.spring-boot-devtools.properties` file.
 This allows you to share the devtools global configuration with applications that are on an older version of Spring Boot that does not support the `$HOME/.config/spring-boot` location.
 
-NOTE: Profiles activated in the above files will not affect the loading of <<spring-boot-features.adoc#boot-features-external-config-profile-specific-properties, profile-specific configuration files>>.
+[NOTE]
+====
+Profiles are not supported in devtools properties/yaml files.
+
+Any profiles activated in `.spring-boot-devtools.properties` will not affect the loading of <<spring-boot-features.adoc#boot-features-external-config-profile-specific-properties, profile-specific configuration files>>.
+Profile specific filenames (of the form `spring-boot-devtools-<profile>.properties`) and `spring.profile` sub-documents in YAML files are not supported.
+====