Fix grammar within ./examples/oauth_desktop.pl

Fix for the following two issues on [line #33 of /examples/oauth_desktop.pl] (https://github.com/semifor/Net-Twitter/blob/master/examples/oauth_desktop.pl#L33)

1. Removed the space character before "Authorize ..." and;
1. Corrected "... continue: " word spelling.

Please let me know if you prefer that I submit Pull Request(s) from a new topic branch too?