[simple] improve margin of #linkto_preferences

Co-authored-by: Paul Braeuning <paul@paulgo.io>

searx/static/themes/simple/src/less/index.less

@@ -1,9 +1,5 @@
 #main_index {
   margin-top: 26vh;
-
-  #linkto_preferences {
-    .ltr-right(1.8rem);
-  }
 }
 
 .index {

searx/static/themes/simple/src/less/style.less

@@ -576,7 +576,7 @@ article[data-vim-selected].category-social {
 
 #linkto_preferences {
   position: absolute;
-  .ltr-right(10px);
+  .ltr-right(1.8rem);
   top: 2.2rem;
   padding: 0;
   border: 0;