Add data-tag-title attribute to tag pills

Fixes #5543

core/ui/TagTemplate.tid

@@ -1,7 +1,7 @@
 title: $:/core/ui/TagTemplate
 
 \whitespace trim
-<span class="tc-tag-list-item">
+<span class="tc-tag-list-item" data-tag-title=<<currentTiddler>>>
 <$set name="transclusion" value=<<currentTiddler>>>
 <$macrocall $name="tag-pill-body" tag=<<currentTiddler>> icon={{!!icon}} colour={{!!color}} palette={{$:/palette}} element-tag="""$button""" element-attributes="""popup=<<qualify "$:/state/popup/tag">> dragFilter='[all[current]tagging[]]' tag='span'"""/>
 <$reveal state=<<qualify "$:/state/popup/tag">> type="popup" position="below" animate="yes" class="tc-drop-down">

core/wiki/macros/tag.tid

@@ -20,7 +20,7 @@ $actions$<$transclude tiddler="""$icon$"""/><$view tiddler=<<__tag__>> field="ti
 \end
 
 \define tag-pill(tag,element-tag:"span",element-attributes:"",actions:"")
-<span class="tc-tag-list-item">
+<span class="tc-tag-list-item" data-tag-title=<<__tag__>>>
 <$macrocall $name="tag-pill-body" tag=<<__tag__>> icon={{{ [<__tag__>get[icon]] }}} colour={{{ [<__tag__>get[color]] }}} palette={{$:/palette}} element-tag="""$element-tag$""" element-attributes="""$element-attributes$""" actions="""$actions$"""/>
 </span>
 \end