Improve label edit buttons labels (#11841)

* Improve label edit buttons labels

Previously when editing the buttons in the "Edit Label" modal were a
strange "Update" and "No". Improved them to "Save" and "Cancel".

Also fixed indentation in the template file, recommended to view changes
with the "Hide whitespace changes" option enabled on GitHub.

* remove unnecessary button icon

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

options/locale/locale_en-US.ini

@@ -71,6 +71,7 @@ issues = Issues
 milestones = Milestones
 
 cancel = Cancel
+save = Save
 add = Add
 add_all = Add All
 remove = Remove

templates/repo/issue/labels/edit_delete_label.tmpl

@@ -48,11 +48,10 @@
 	</div>
 	<div class="actions">
 		<div class="ui negative button">
-				{{.i18n.Tr "modal.no"}}
+			{{.i18n.Tr "cancel"}}
 		</div>
-			<div class="ui positive right labeled icon button">
-				{{.i18n.Tr "modal.modify"}}
-				<i class="checkmark icon"></i>
+		<div class="ui positive button">
+			{{.i18n.Tr "save"}}
 		</div>
 	</div>
 </div>