DocBook reader: drop period in formalpara title...

...and put it in a div with class `formalpara-title`, so that
people can reformat with filters.

Closes #6562.

Thanks to rdmuller.

src/Text/Pandoc/Readers/DocBook.hs

@@ -782,8 +782,8 @@ parseBlock (Elem e) =
         "para"  -> parseMixed para (elContent e)
         "formalpara" -> do
            tit <- case filterChild (named "title") e of
-                        Just t  -> para . strong . (<> str ".") <$>
-                                     getInlines t
+                        Just t  -> divWith ("",["formalpara-title"],[]) .
+                                   para .  strong <$> getInlines t
                         Nothing -> return mempty
            (tit <>) <$> parseMixed para (elContent e)
         "simpara"  -> parseMixed para (elContent e)