Restyle code element, remove docs example overflow, improve docs examples (#25054)

* Restyle code element, clean up variables

- Removes the padding and background-color
- Changes the color to a brand color ()
- Add new variables to kbd element styles to account for removing the code ones
- Remove overrides that were needed previously

* only break between words, and override it in the pre

* make file inputs 100% wide

* scope custom file changes in input group for sizing

* shorter button labels for responsive

* narrower cards

* button was too wide

* downsize

* fewer links in pagination

* redo cell text

* improve overflow docs

docs/4.0/components/dropdowns.md

@@ -563,7 +563,7 @@ By default, a dropdown menu is automatically positioned 100% from the top and al
 {% example html %}
 <div class="btn-group">
   <button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
-    This dropdown's menu is right-aligned
+    Right-aligned menu
   </button>
   <div class="dropdown-menu dropdown-menu-right">
     <button class="dropdown-item" type="button">Action</button>