Add left padding for chunk header of split diff view (#13397)

This commit adds 10px padding-left on chunk header element
(which is `<span>`).

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>

Co-authored-by: zeripath <art27@cantab.net>

web_src/less/_repository.less

@@ -1711,6 +1711,10 @@
     }
 
     .code-diff-split {
+      .tag-code .lines-code code.code-inner {
+        padding-left: 10px !important;
+      }
+
       table,
       tbody {
         width: 100%;