Add how-to for available PlantUML style parameters

ALL-for-build/Makedir/sphinxcontrib-plantuml/typo3_styles.iuml

@@ -1,10 +1,16 @@
 '
 ' TYPO3 PlantUML Stylesheet
-' @see https://plantuml-documentation.readthedocs.io/en/latest/formatting/all-skin-params.html
+'
+' Parameters:
+' Get all available style parameters at the command line of this Docker container:
+' # source <(docker run --rm t3docs/render-documentation show-shell-commands)
+' # dockrun_t3rd /bin/bash
+' # plantuml -language
+' => search for "skinparameter"
 '
 ' Icons:
 ' Preprocessor directives like !include, !define, etc. are not supported in this global stylesheet when rendered by
-' PlantUML v2017.15 - which is used in the current TYPO3 docs rendering process - such that
+' PlantUML v2017.15 - which is used in the current TYPO3 documentation rendering process - such that
 ' custom macros and sprites cannot be provided globally. In newer versions of PlantUML, icons can be
 ' provided globally by
 '   - including custom sprites and macros in this file