add aria-label to tag edit fields (#4231)

chrome/content/zotero/elements/tagsBox.js

@@ -264,6 +264,7 @@
 			valueElement.setAttribute('flex', 1);
 			valueElement.setAttribute('nowrap', true);
 			valueElement.setAttribute('tight', true);
+			document.l10n.setAttributes(valueElement, "tag-field");
 			valueElement.className = 'zotero-box-label';
 			valueElement.readOnly = !this.editable;
 			valueElement.value = valueText;

chrome/locale/en-US/zotero/zotero.ftl

@@ -11,6 +11,7 @@ general-remind-me-later = Remind Me Later
 general-choose-file = Choose File…
 general-open-settings = Open Settings
 general-help = Help
+general-tag = Tag
 
 menu-file-show-in-finder =
     .label = Show in Finder
@@ -516,6 +517,9 @@ expand-all-sections =
 abstract-field =
     .placeholder = Add abstract…
 
+tag-field =
+    .aria-label = { general-tag }
+
 tagselector-search =
     .placeholder = Filter Tags