Updated text expander text color

app/assets/stylesheets/pages/commits.scss

@@ -39,7 +39,7 @@
   .text-expander {
     display: inline-block;
     background: $gray-light;
-    color: $gl-gray-dark;
+    color: $gl-placeholder-color;
     padding: 0 5px;
     cursor: pointer;
     border: 1px solid $border-gray-dark;