format css, tweak example image

Author: mlange-42

guide/src/format/images/rust-logo-blk-dark.svg

@@ -1,8 +1,8 @@
-.light .no-light {
-    display: none;
-}
-
-.rust .no-rust {
+.light .no-light,
+.rust .no-rust,
+.navy .no-navy,
+.ayu .no-ayu,
+.coal .no-coal {
     display: none;
 }
 
@@ -11,18 +11,6 @@
     display: none;
 }
 
-.navy .no-navy {
-    display: none;
-}
-
-.ayu .no-ayu {
-    display: none;
-}
-
-.coal .no-coal {
-    display: none;
-}
-
 .navy .no-dark-themes,
 .ayu .no-dark-themes,
 .coal .no-dark-themes {