fix markdown syntax

Author: yorkie

_posts/2015-04-19-clock.md

@@ -38,5 +38,5 @@ clock <command> [<task>] [-m <message>] [-f <clockfile>] [-t <dir>]
 -  `-f|--file`         where to save the clocks, defaults to $HOME/.clocks
 
 # Links
-* [Source Code][https://github.com/lordvlad/clock]
-* [Author][https://github.com/lordvlad]
+* [Source Code](https://github.com/lordvlad/clock)
+* [Author](https://github.com/lordvlad)