Add reST usage tips

extension/Documentation/Manual.rst

@@ -17,6 +17,7 @@
 ..
 .. Admonitions (https://docs.typo3.org/typo3cms/drafts/github/xperseguers/RstPrimer/#admonitions)
 ..       .. note::    .. important::     .. tip::      .. warning::
+.. Color:   (grey)       (orange)           (green)      (red)
 ..
 .. Definition:
 .. some text becomes strong (only one line)