use nesting to make .table-striped & .table-hover mixin-able again; fixes #11387

less/tables.less

@@ -104,11 +104,13 @@ th {
 //
 // Default zebra-stripe styles (alternating gray and transparent backgrounds)
 
-.table-striped > tbody > tr:nth-child(odd) {
+.table-striped {
+  > tbody > tr:nth-child(odd) {
     > td,
     > th {
       background-color: @table-bg-accent;
     }
+  }
 }
 
 
@@ -116,11 +118,13 @@ th {
 //
 // Placed here since it has to come after the potential zebra striping
 
-.table-hover > tbody > tr:hover {
+.table-hover {
+  > tbody > tr:hover {
     > td,
     > th {
       background-color: @table-bg-hover;
     }
+  }
 }