Add proper formatting for spoiler/nsfw sub-tags

tildes/scss/modules/_label.scss

@@ -18,7 +18,7 @@
   max-width: 100%;
 }
 
-.label-topic-tag-nsfw,
-.label-topic-tag-spoiler {
+.label-topic-tag[class*='label-topic-tag-nsfw'],
+.label-topic-tag[class*='label-topic-tag-spoiler'] {
   font-weight: bold;
 }

tildes/scss/themes/_theme_base.scss

@@ -291,11 +291,11 @@
     }
   }
 
-  .label-topic-tag-nsfw {
+  .label-topic-tag[class*='label-topic-tag-nsfw'] {
     @include theme-special-label(map-get($theme, "topic-tag-nsfw"), $is-light);
   }
 
-  .label-topic-tag-spoiler {
+  .label-topic-tag[class*='label-topic-tag-spoiler'] {
     @include theme-special-label(map-get($theme, "topic-tag-spoiler"), $is-light);
   }