docs(contributing): fix typo

- Remove redundant word

Author: prayagverma

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 Firstly, please go over our FAQ: https://github.com/angular-ui/bootstrap/wiki/FAQ
 
-Please, do not open issues for the general support questions as we want to keep GitHub issues for bug reports and feature requests. You've got much better chances of getting your question answered on [StackOverflow](http://stackoverflow.com/questions/tagged/angular-ui-bootstrap) where maintainers are looking at questions questions tagged with `angular-ui-bootstrap`.
+Please, do not open issues for the general support questions as we want to keep GitHub issues for bug reports and feature requests. You've got much better chances of getting your question answered on [StackOverflow](http://stackoverflow.com/questions/tagged/angular-ui-bootstrap) where maintainers are looking at questions tagged with `angular-ui-bootstrap`.
 
 StackOverflow is a much better place to ask questions since:
 * there are hundreds of people willing to help on StackOverflow