Fix a few Sphinx typos
Fix a few Sphinx typos

* `.. note:` -> `.. note::` to prevent the `note` from being interpreted as a comment, which wouldn't show up when the docs are rendered.
* Double backticks for the code bits.
* Correct typo ("atribute" -> "attribute").
* Sphinx doesn't like characters immediately after the backticks, so add a hyphen in to prevent it from being rendered incorrectly.
13steinj/praw,gschizas/praw,leviroth/praw,gschizas/praw,praw-dev/praw,13steinj/praw,leviroth/praw,praw-dev/praw