Timeline Title for small resolution Add to knowledge base button. (#9926)

* Add to Knowledge Base button class updated to hide for mobile view.

* Updated code to avoid multiple occurance of Knowledge Base button while updating comment.
diff --git a/erpnext/support/doctype/issue/issue.js b/erpnext/support/doctype/issue/issue.js
index 2bee422..bef8cb4 100644
--- a/erpnext/support/doctype/issue/issue.js
+++ b/erpnext/support/doctype/issue/issue.js
@@ -20,9 +20,11 @@
 	timeline_refresh: function(frm) {
 		// create button for "Add to Knowledge Base"
 		if(frappe.model.can_create('Help Article')) {
-			$('<button class="btn btn-xs btn-default btn-add-to-kb pull-right" style="margin-top: -2px">'+
+			// Removing Knowledge Base button if exists to avoid multiple occurance
+			frm.timeline.wrapper.find('.comment-header .asset-details .btn-add-to-kb').remove();
+			$('<button class="btn btn-xs btn-default btn-add-to-kb hidden-xs pull-right" style="margin-top: -2px">'+
 				__('Add to Knowledge Base') + '</button>')
-				.appendTo(frm.timeline.wrapper.find('.comment-header'))
+				.appendTo(frm.timeline.wrapper.find('.comment-header .asset-details'))
 				.on('click', function() {
 					var content = $(this).parents('.timeline-item:first').find('.timeline-item-content').html();
 					var doc = frappe.model.get_new_doc('Help Article');