fix(templating): small fixed toplaceholder text in template variable editor

public/app/features/templating/partials/editor.html

@@ -246,7 +246,7 @@
 								Tag values query
 							</li>
 							<li>
-								<input type="text" style="width: 588px" class="input tight-form-input last" ng-model='current.tagValuesQuery' placeholder="apps.$__tag.*" ng-model-onblur></input>
+								<input type="text" style="width: 588px" class="input tight-form-input last" ng-model='current.tagValuesQuery' placeholder="apps.$tag.*" ng-model-onblur></input>
 							</li>
 						</ul>
 						<div class="clearfix"></div>