Prep for v4.2.0 release

- Move 4.1 docs to 4.2
- Update versions everywhere to 4.1.3 with release script
- Manually bump the shorthand version in package.json
- Add 4.2 to the versions docs page
- Update some redirects
- Fix tests asset URLs
- Bump Nuget and more

site/docs/4.2/utilities/clearfix.md

@@ -0,0 +1,39 @@
+---
+layout: docs
+title: Clearfix
+description: Quickly and easily clear floated content within a container by adding a clearfix utility.
+group: utilities
+toc: true
+---
+
+Easily clear `float`s by adding `.clearfix` **to the parent element**. Can also be used as a mixin.
+
+{% highlight html %}
+<div class="clearfix">...</div>
+{% endhighlight %}
+
+{% highlight scss %}
+// Mixin itself
+@mixin clearfix() {
+  &::after {
+    display: block;
+    content: "";
+    clear: both;
+  }
+}
+
+// Usage as a mixin
+.element {
+  @include clearfix;
+}
+{% endhighlight %}
+
+The following example shows how the clearfix can be used. Without the clearfix the wrapping div would not span around the buttons which would cause a broken layout.
+
+{% capture example %}
+<div class="bg-info clearfix">
+  <button type="button" class="btn btn-secondary float-left">Example Button floated left</button>
+  <button type="button" class="btn btn-secondary float-right">Example Button floated right</button>
+</div>
+{% endcapture %}
+{% include example.html content=example %}