fix($core): update outbound link icon alignment (#1308)

gtsiolis · ulivz · commit 6de1c309a0f7 · 2019-02-25T00:04:54.000+08:00
diff --git a/packages/@vuepress/core/lib/app/components/OutboundLink.vue b/packages/@vuepress/core/lib/app/components/OutboundLink.vue
@@ -9,4 +9,7 @@
 .icon.outbound
   color #aaa
   display inline-block
+  vertical-align middle
+  position relative
+  top -1px
 </style>
