fixes #7977: prevent some table bullshit on input groups

docs/assets/css/bootstrap.css

@@ -1679,6 +1679,7 @@ input[type="color"].input-small {
 
 .input-group {
   display: table;
+  border-collapse: separate;
 }
 
 .input-group.col {

less/forms.less

@@ -291,6 +291,7 @@ input[type="color"] {
 // -------------------------
 .input-group {
   display: table;
+  border-collapse: separate; // prevent input groups from inheriting border styles from table cells when placed within a table
 
   // Undo padding and float of grid classes
   &.col {