Introduce x-axe scrolling to code-blocks.

This improvement introduces x-axe scrolling to code-blocks by
overriding certain default bootstrap word-wrapping constraints.

This PR closes: https://github.com/dotcloud/docker/issues/5279

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)

docs/theme/mkdocs/css/base.css

@@ -59,6 +59,11 @@ h6,
   padding: 0.5em 0.75em !important;
   line-height: 1.8em;
   background: #fff;
+  overflow-x: auto;
+}
+#content pre code {
+  word-wrap: normal;
+  white-space: pre;
 }
 #content blockquote {
   background: #fff;