Clean up plugin READMEs and a few plugins

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

plugins/yii/README.md

@@ -3,7 +3,8 @@
 The plugin adds autocomplete commands and subcommands for [yii](https://www.yiiframework.com/).
 
 To use it, add `yii` to the plugins array of your zshrc file:
-```
+
+```zsh
 plugins=(... yii)
 ```