fix css for del code

public/ng/less/gogs/repository.less

@@ -653,12 +653,18 @@
                         background-color: #E0E0E0 !important;
                         border-color: #ADADAD !important;
                     }
+                    td.selected-line, td.selected-line pre {
+                        background-color: #ffffdd !important;
+                    }
                 }
                 &.del-code {
                     td, pre {
                         background-color: #ffe2dd !important;
                         border-color: #e9aeae !important;
                     }
+                    td.selected-line, td.selected-line pre {
+                        background-color: #ffffdd !important;
+                    }
                 }
                 &.add-code {
                     td, pre {