README: fix typos. (#364)

Author: be-we

README.md

@@ -86,15 +86,15 @@ when you click on your username.
 9. Hit Subscribe and you are finished, that address book is added
 10. Repeat for any additional address books
 
-#### Thunderbird (using TbSync, for Thurderbird older than version 91)
+#### Thunderbird (using TbSync, for Thunderbird older than version 91)
 1. Install [TbSync](https://addons.thunderbird.net/en-us/thunderbird/addon/tbsync/) and the accompanying [DAV provider](https://addons.thunderbird.net/en-us/thunderbird/addon/dav-4-tbsync/).
 2. Open the TbSync window: Edit -> TbSync
 3. Add new DAV account (choose manual configuration).
 4. Use `http://localhost:37358/` for both servers, your EteSync username as the username and the DAV password you got in [configuration and running](#configuration-and-running) as the password.
 
 **Note:** if you enabled SSL in etesync-dav, you should follow the [TbSync instructions for self-signed certificates](https://github.com/jobisoft/TbSync/wiki/How-to-use-TbSync-with-self-signed-or-otherwise-untrusted-certificates%3F).
 
-#### Thunderbird (no additional add-ons, for Thurderbird older than version 91)
+#### Thunderbird (no additional add-ons, for Thunderbird older than version 91)
 TbSync includes address book support (Lightning does not), automatically discovers all your calendars/address books/tasks, and just works better in general than this solution for versions of Thunderbird older than 91. However, you *can* also do the following:
 
 1. Install a CardDAV add-on such as Cardbook if you want to sync your contacts