new rule: requireHyphenBeforeDescription

#50

This might need some more tests?

I'm assuming most people want the space so its like ` - description` not ` -description`

so it works like ` if (tag.description.substring(0, 2) !== '- ') {` 


@hzoo Agreed. I'm not native english speaker so If you find some mistakes feel free to fix that. This project need a lot of rules to systemize and formalize generic jsdoc stylistic requirements so any ideas are welcome. It needs meat ;-D

Btw. Fix them all here if you can with separated commits, it would be great