Text-slicer: add support for exclude filters

The exclude filter `+[tag[intro]]` will produce a document that only
includes the paragraphs with the tag “intro”. These are derived from
the paragraphs in the original document with the CSS class “intro”.

plugins/tiddlywiki/text-slicer/templates/interactive/document.tid

@@ -21,10 +21,14 @@ $:/config/plugins/tiddlywiki/text-slicer/heading-status/$(currentTiddler)$
 
 <$set name="tv-show-toolbar" value={{$(config-show-toolbar)$}}>
 
+<$set name="tv-exclude-filter" value={{!!toc-exclude-filter}}>
+
 <$list filter="[list<currentTiddler>!has[draft.of]]" template="$:/plugins/tiddlywiki/text-slicer/templates/interactive/tiddler" listItem="item"/>
 
 </$set>
 
+</$set>
+
 </div>
 
 </div>