[MDEP-669] Optimize the documentation of <outputProperty> of build-cl…

…asspath mojo

Co-authored-by: Elliotte Rusty Harold <elharo@apache.org>

This closes #283

src/main/java/org/apache/maven/plugins/dependency/fromDependencies/BuildClasspathMojo.java

@@ -86,7 +86,7 @@ public class BuildClasspathMojo extends AbstractDependencyFilterMojo implements
     private String prefix;
 
     /**
-     * A property to set to the content of the classpath string.
+     * If defined, the name of a property to which the classpath string will be written.
      */
     @Parameter(property = "mdep.outputProperty")
     private String outputProperty;