anchor.diff:  
   For example:
   
  -[source,java]
  +.Java
  +[source,java,role="primary"]
   ----
   @Command(name = "defaults", mixinStandardHelpOptions = true, version = "defaults 0.1")
   public class DefaultValueDemo implements Runnable {
  
positive.code:     }
  }
  ----
  Gives the following results:
  [source, bash]
  ----
  
negative.code: class Git { }
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  import picocli.CommandLine.PropertiesDefaultProvider;
  // ...
  @Command(name = "git", defaultValueProvider = PropertiesDefaultProvider::class)
  class Git { }
  ----
  
  The above will try to load default values from `new File(System.getProperty("user.home"), ".git.properties")`.
  The location of the properties file can also be controlled with system property `"picocli.defaults.${COMMAND-NAME}.path"` (`"picocli.defaults.git.path"` in this example), in which case the value of the property must be the path to the file containing the default values.
  
  The location of the properties file may also be specified programmatically. For example:
  
  .Java
  [source,java,role="primary"]
  ----
  CommandLine cmd = new CommandLine(new MyCommand());
  File defaultsFile = new File("path/to/config/mycommand.properties");
  cmd.setDefaultValueProvider(new PropertiesDefaultProvider(defaultsFile));
  cmd.execute(args);
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  val cmd = CommandLine(MyCommand())
  val defaultsFile = File("path/to/config/mycommand.properties")
  cmd.defaultValueProvider = PropertiesDefaultProvider(defaultsFile)
  cmd.execute(*args)
  ----
  
  ==== PropertiesDefaultProvider Format
  