minor #7842 Fix the link to ConEmu (it is now hosted on GitHub) (Calinou)

This PR was merged into the 2.7 branch.

Discussion
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Fix the link to ConEmu (it is now hosted on GitHub)

This updates the link to ConEmu to the GitHub Pages website, since Google Code has closed last year.

Commits
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b568325 Fix the link to ConEmu (it is now hosted on GitHub)

Author: xabbuh

contributing/code/tests.rst

@@ -55,6 +55,6 @@ what's going on and if the tests are broken because of the new code.
     to see colored test results.
 
 .. _Cmder: http://cmder.net/
-.. _ConEmu: https://code.google.com/p/conemu-maximus5/
+.. _ConEmu: https://conemu.github.io/
 .. _ANSICON: https://github.com/adoxa/ansicon/releases
 .. _Mintty: https://mintty.github.io/