Clean up plugin READMEs and a few plugins

- fasd
- history
- mercurial
- pylint
- repo
- yii2

plugins/gas/README.md

@@ -4,6 +4,7 @@ This plugin adds autocompletion for the [gas](http://walle.github.com/gas) comma
 a utility to manage Git authors.
 
 To use it, add `gas` to the plugins array of your zshrc file:
+
 ```zsh
 plugins=(... gas)
 ```