Fix typo in Git and GitHub task (kottans#322)

Author: boxdxnx

tasks/git-intro.md

@@ -41,7 +41,7 @@ Get familiar with Git and GitHub.
     * Merge master branch into your feature branch: `git checkout BRANCH_NAME && git merge master`
     * Resolve any merge conflicts if there are any
     * Push feature branch to your remote repository: `git push --set-upstream origin BRANCH_NAME`
-    * Make pull-request from your repository to this repository via GitHub web-interface
+    * Make pull-request from your repository to [this][mock-repo] repository via GitHub web-interface
     * If you are asked to fix a merge conflict refer to the extra materials for the related information
 
     **Please note, that your PR may not be reviewed quickly.**