Add alternative text for images

src/webui/www/private/views/filters.html

@@ -1,6 +1,6 @@
 <div class="filterWrapper">
     <span class="filterTitle" onclick="toggleFilterDisplay('status');">
-        <img src="images/go-down.svg">QBT_TR(Status)QBT_TR[CONTEXT=TransferListFiltersWidget]
+        <img src="images/go-down.svg" alt="QBT_TR(Collapse/expand)QBT_TR[CONTEXT=TransferListFiltersWidget]">QBT_TR(Status)QBT_TR[CONTEXT=TransferListFiltersWidget]
     </span>
     <ul class="filterList" id="statusFilterList">
         <li id="all_filter"><a href="#" onclick="setFilter('all');return false;"><img src="images/filter-all.svg" alt="All" />QBT_TR(All (0))QBT_TR[CONTEXT=StatusFilterWidget]</a></li>
@@ -20,21 +20,21 @@
 </div>
 <div class="filterWrapper">
     <span class="filterTitle" onclick="toggleFilterDisplay('category');">
-        <img src="images/go-down.svg">QBT_TR(Categories)QBT_TR[CONTEXT=TransferListFiltersWidget]
+        <img src="images/go-down.svg" alt="QBT_TR(Collapse/expand)QBT_TR[CONTEXT=TransferListFiltersWidget]">QBT_TR(Categories)QBT_TR[CONTEXT=TransferListFiltersWidget]
     </span>
     <ul class="filterList" id="categoryFilterList">
     </ul>
 </div>
 <div class="filterWrapper">
     <span class="filterTitle" onclick="toggleFilterDisplay('tag');">
-        <img src="images/go-down.svg">QBT_TR(Tags)QBT_TR[CONTEXT=TransferListFiltersWidget]
+        <img src="images/go-down.svg" alt="QBT_TR(Collapse/expand)QBT_TR[CONTEXT=TransferListFiltersWidget]">QBT_TR(Tags)QBT_TR[CONTEXT=TransferListFiltersWidget]
     </span>
     <ul class="filterList" id="tagFilterList">
     </ul>
 </div>
 <div class="filterWrapper">
     <span class="filterTitle" onclick="toggleFilterDisplay('tracker');">
-        <img src="images/go-down.svg">QBT_TR(Trackers)QBT_TR[CONTEXT=TransferListFiltersWidget]
+        <img src="images/go-down.svg" alt="QBT_TR(Collapse/expand)QBT_TR[CONTEXT=TransferListFiltersWidget]">QBT_TR(Trackers)QBT_TR[CONTEXT=TransferListFiltersWidget]
     </span>
     <ul class="filterList" id="trackerFilterList">
     </ul>