Merge branch 'rs-code-links' into 'master'

Make `code` elements in links display as such

When a link consisted only of an inline code block -- ```[`like this`](https://google.com/)``` -- it was hard to tell that it was even a link.

Before:

> ![Screen_Shot_2015-07-31_at_5.45.06_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/eda0a0630024d461c8de151d06e9f4db/Screen_Shot_2015-07-31_at_5.45.06_PM.png)

After:

> ![Screen_Shot_2015-07-31_at_5.43.15_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/9542c49cfb4d43c015d464ef0ba0440f/Screen_Shot_2015-07-31_at_5.43.15_PM.png)


See merge request !1082

app/assets/stylesheets/base/mixins.scss

@@ -70,7 +70,7 @@
     font-family: $monospace_font;
     white-space: pre;
     word-wrap: normal;
-    padding: 0;
+    padding: 1px 2px;
   }
 
   kbd {

app/assets/stylesheets/generic/typography.scss

@@ -38,6 +38,10 @@ code {
   }
 }
 
+a > code {
+  color: $link-color;
+}
+
 /**
  * Wiki typography
  *