Merge branch 'v4-dev' of https://github.com/twbs/bootstrap into v4-dev

docs/4.0/components/input-group.md

@@ -8,7 +8,7 @@ toc: true
 
 ## Basic example
 
-Place one add-on or button on either side of an input. You may also place one on both sides of an input. **We do not support multiple form-controls in a single input group** and `<label>`s must come outside the input group.
+Place one add-on or button on either side of an input. You may also place one on both sides of an input. Remember to place `<label>`s outside the input group.
 
 {% capture example %}
 <div class="input-group mb-3">