Update the best practices documentation

This change replaces an internal link with an external one from the
Google style guide. It also repairs a broken markdown link.

BUG=799576
TEST=Launch md_browser with http://localhost:8080/docs/documentation_best_practices.md

Change-Id: I816aefde95fbbf0d3a365504993e251e5961cc66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1570573
Reviewed-by: Dirk Pranke <[email protected]>
Commit-Queue: Dirk Pranke <[email protected]>
Cr-Commit-Position: refs/heads/master@{#651569}
diff --git a/docs/documentation_best_practices.md b/docs/documentation_best_practices.md
index 4e4df45..623e18b 100644
--- a/docs/documentation_best_practices.md
+++ b/docs/documentation_best_practices.md
@@ -1,7 +1,7 @@
 # Documentation Best Practices
 
-"Say what you mean, simply and directly." - [Brian Kernighan]
-(http://en.wikipedia.org/wiki/The_Elements_of_Programming_Style)
+"Say what you mean, simply and directly." -
+[Brian Kernighan](http://en.wikipedia.org/wiki/The_Elements_of_Programming_Style)
 
 [TOC]
 
@@ -43,7 +43,7 @@
 
 Documentation is an art. There is no perfect document, there are only proven
 methods and prudent guidelines. See
-go/g3doc-style#good.
+[Better is better than perfect](https://github.com/google/styleguide/blob/gh-pages/docguide/philosophy.md#better-is-better-than-perfect).
 
 ## Documentation is the story of your code