[code coverage] Update mailing list to code-coverage@chromium

This CL updates the md doc's mailing list to code-coverage@chromium.

Change-Id: Ifb620a543b4afb13239cf8736832448047787aba
Reviewed-on: https://chromium-review.googlesource.com/c/1311089Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604416}

docs/code_coverage.md

@@ -161,7 +161,7 @@ For more information on how to use llvm-cov, please refer to the [guide].
 For any breakage report and feature requests, please [file a bug].
 
 ### Mailing list
-For questions and general discussions, please join [chrome-code-coverage group].
+For questions and general discussions, please join [code-coverage group].
 
 ## FAQ
 
@@ -247,7 +247,7 @@ information, see [crbug.com/842424].
 
 
 [assert]: http://man7.org/linux/man-pages/man3/assert.3.html
-[chrome-code-coverage group]: https://groups.google.com/a/google.com/forum/#!forum/chrome-code-coverage
+[code-coverage group]: https://groups.google.com/a/chromium.org/forum/#!forum/code-coverage
 [code-coverage repository]: https://chrome-internal.googlesource.com/chrome/tools/code-coverage
 [coverage dashboard]: https://chromium-coverage.appspot.com/
 [coverage script]: https://cs.chromium.org/chromium/src/tools/code_coverage/coverage.py