Replace show/hide torrent group symbols

static/styles/bookish/scss/layout.scss

 .show_torrents {
     width: 21px;
     height: 28px;
-    background: url("/static/common/forums/show2.png") no-repeat center center;
+    background: url("/static/common/symbols/show.png") no-repeat center center;
 }
 
 .hide_torrents {
     width: 21px;
     height: 28px;
-    background: url("/static/common/forums/hide2.png") no-repeat center center;
+    background: url("/static/common/symbols/hide.png") no-repeat center center;
 }
 
 .show_torrents_link {

static/styles/matcha/scss/matcha.scss

 .show_torrents {
     width: 21px;
     height: 28px;
-    background: url("images/show2.png") no-repeat center center;
+    background: url("/static/common/symbols/hide.png") no-repeat center center;
 }
 
 .hide_torrents {
     width: 21px;
     height: 28px;
-    background: url("images/hide2.png") no-repeat center center;
+    background: url("/static/common/symbols/hide.png") no-repeat center center;
 }
 
 .show_torrents_link {

static/styles/oppai/scss/oppai.scss

 .show_torrents {
     width: 21px;
     height: 28px;
-    background: url("/static/common/forums/show2.png") no-repeat center center;
+    background: url("/static/common/symbols/show.png") no-repeat center center;
 }
 
 .hide_torrents {
     width: 21px;
     height: 28px;
-    background: url("/static/common/forums/hide2.png") no-repeat center center;
+    background: url("/static/common/symbols/hide.png") no-repeat center center;
 }
 
 .show_torrents_link {