Fixed grammatical errors in CONTRIBUTING.md (#5555)

Author: mitheelgajare

CONTRIBUTING.md

@@ -8,7 +8,7 @@ Welcome to [TheAlgorithms/Python](https://github.com/TheAlgorithms/Python)! Befo
 
 ### Contributor
 
-We are very happy that you consider implementing algorithms and data structure for others! This repository is referenced and used by learners from all over the globe. Being one of our contributors, you agree and confirm that:
+We are very happy that you consider implementing algorithms and data structures for others! This repository is referenced and used by learners from all over the globe. Being one of our contributors, you agree and confirm that:
 
 - You did your work - no plagiarism allowed
   - Any plagiarized work will not be merged.
@@ -25,7 +25,7 @@ We appreciate any contribution, from fixing a grammar mistake in a comment to im
 
 Your contribution will be tested by our [automated testing on Travis CI](https://travis-ci.org/TheAlgorithms/Python/pull_requests) to save time and mental energy.  After you have submitted your pull request, you should see the Travis tests start to run at the bottom of your submission page.  If those tests fail, then click on the ___details___ button try to read through the Travis output to understand the failure.  If you do not understand, please leave a comment on your submission page and a community member will try to help.
 
-Please help us keep our issue list small by adding fixes: #{$ISSUE_NO} to the commit message of pull requests that resolve open issues. GitHub will use this tag to auto close the issue when the PR is merged.
+Please help us keep our issue list small by adding fixes: #{$ISSUE_NO} to the commit message of pull requests that resolve open issues. GitHub will use this tag to auto-close the issue when the PR is merged.
 
 #### What is an Algorithm?