Extract placeholder selector for SDG list styles

app/assets/stylesheets/mixins.scss

@@ -227,6 +227,16 @@
   }
 }
 
+%sdg-goal-list {
+  list-style: none;
+  margin-bottom: 0;
+  margin-left: 0;
+
+  li {
+    display: inline-block;
+  }
+}
+
 %tags {
   margin-bottom: 0;
   margin-left: 0;

app/assets/stylesheets/sdg/goals/index.scss

@@ -1,14 +1,12 @@
 .sdg-goals-index {
 
   .sdg-goal-list {
+    @extend %sdg-goal-list;
     @include grid-row;
     @include grid-column-gutter;
-    list-style: none;
-    margin-bottom: 0;
     max-width: 40rem;
 
     li {
-      display: inline-block;
       $spacing: 1vw;
 
       line-height: 0;

app/assets/stylesheets/sdg/goals/tag_list.scss

@@ -1,10 +1,7 @@
 .sdg-goal-tag-list {
-  list-style: none;
+  @extend %sdg-goal-list;
-  margin-bottom: 0;
-  margin-left: 0;
 
   li {
-    display: inline-block;
     margin-bottom: 1ch;
 
     &:not(:last-child) {

app/assets/stylesheets/sdg/related_list_selector.scss

@@ -13,12 +13,9 @@
   }
 
   label + ul {
-    list-style: none;
+    @extend %sdg-goal-list;
-    margin-bottom: 0;
-    margin-left: 0;
 
     li {
-      display: inline-block;
 
       &[aria-checked=true] img {
         opacity: 0.15;