anchor.diff:  
   For options and positional parameters, the optional annotation attribute `descriptionKey` can be used to localize the description. For example:
   
  -[source,java]
  +.Java
  +[source,java,role="primary"]
   ----
   @Option(names = "-x", descriptionKey = "xoption") int x;
   ----
  +
  +.Kotlin
  +[source,kotlin,role="secondary"]
  +----
  +@Option(names = ["-x"], descriptionKey = "xoption") var x = 0
  +----
  +
   The matching entry in the resource bundle could look like this:
   ----
   xoption = This is the description for the -x option.
  
positive.code: 
  When the `descriptionKey` is omitted, the https://picocli.info/apidocs/picocli/CommandLine.Option.html#descriptionKey--[fallback for options] is any option name without the leading dashes, for example:
  
  [source,java]
  ----
  @Option(names = {"-v", "--verbose"}) boolean[] verbose;
  ----
  
  The matching entry in the resource bundle could look like this:
  
negative.code: 
  For https://picocli.info/apidocs/picocli/CommandLine.Parameters.html#descriptionKey--[positional parameters] the fallback key is the `paramLabel + [ index ]`, for example:
  
  .Java
  [source,java,role="primary"]
  ----
  @Parameters(index = "0..*", paramLabel="FILES") File[] files;
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  @Parameters(index = "0..*", paramLabel = "FILES") lateinit var files: Array<File>
  ----
  
  The matching entry in the resource bundle could look like this:
  ----
  FILES[0..*] = The files to process.
  ----
  
  For argument groups, use the `headingKey` to specify a resource bundle key. For example:
  
  .Java
  [source,java,role="primary"]
  ----
  @ArgGroup(headingKey = "myBundleKey") MyArgGroup myGroup;
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  @ArgGroup(headingKey = "myBundleKey") lateinit var myGroup: MyArgGroup
  ----
  
  The matching entry in the resource bundle could look like this:
  ----
  myBundleKey = The localized heading for this argument group%n
  