Fixes #17230: Renames .navbar-static-top to .navbar-full and adds docs for it

docs/components/navbar.md

@@ -163,7 +163,13 @@ Although it's not required, you can wrap a navbar in a `.container` to center it
 
 ## Placement
 
-Navbars can be statically placed (their default behavior), or fixed to the top or bottom of the viewport.
+Navbars can be statically placed (their default behavior), static without rounded corners, or fixed to the top or bottom of the viewport.
+
+{% example html %}
+<nav class="navbar navbar-full navbar-light bg-faded">
+  <a class="navbar-brand" href="#">Full width</a>
+</nav>
+{% endexample %}
 
 {% example html %}
 <nav class="navbar navbar-fixed-top navbar-light bg-faded">

scss/_navbar.scss

@@ -19,8 +19,8 @@
 // Display the navbar across the entirety of the page or fixed it to the top or
 // bottom of the page.
 
-// Static top (unfixed, but 100% wide) navbar
-.navbar-static-top {
+// A static, full width modifier with no rounded corners.
+.navbar-full {
   z-index: $zindex-navbar;
 
   @include media-breakpoint-up(sm) {