Polishing.

Author: mp911de

src/main/antora/modules/ROOT/pages/value-expressions.adoc

@@ -239,7 +239,7 @@ You can find real-life context extensions at https://github.com/spring-projects/
 [[valueexpressions.property-placeholders]]
 == Property Placeholders
 
-Property placeholders refer to properties provided typically by a `PropertySource` through `Environment`.
+Property placeholders following the form `${…}` refer to properties provided typically by a `PropertySource` through `Environment`.
 Properties are useful to resolve against system properties, application configuration files, environment configuration or property sources contributed by secret management systems.
 You can find more details on the property placeholders in {spring-framework-docs}/core/beans/annotation-config/value-annotations.html#page-title[Spring Framework's documentation on `@Value` usage].