the formatplus plugin almost does what you want. It uses
!! instead of
,, . You can easily modify it.
install the plugin, then with a notepad, edit the file
lib/plugins/formatplus/syntax/smallcapsplus.php . do a global search and replace : replace every
,,. Save and exit your notepad. Ask your search engine how to clear your browser cache, how to clear DokuWiki cache, purge your browser cache, clear DW cache, you're all set.