Fixed a typing and a grammatical error in the guide to contributing.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

CONTRIBUTING.md

@@ -1,7 +1,7 @@
 The most common form of contribution to any open source project are bug reports.
 We always welcome them because we want to be aware of any shortcomings in our code in order to make the product better.
-However, as much as we would love to to fix all reported issues in a timely manner, unfortunately we do not always have the resources to do so.
-Therefore we would like to ask for your help by either of:
+However, as much as we would love to fix all reported issues in a timely manner, unfortunately we do not always have the resources to do so.
+Therefore we would like to ask you to help by either of:
 
 1. Fixing the problem and sending us a pull request instead of working around issues with your own custom passes or in other ways.
 In most cases the former is no more difficult and takes just as much time. Besides, we are always here to help;