Who have to close fixed issue?!

[Denis Shelomovskij]

Who have to close the issue? Is it issue reporter, pull sender or pull 
committer? More and more issues are now fixed but not closed.

I have asked it here
https://github.com/D-Programming-Language/druntime/pull/286#issuecomment-7650357
and here
https://github.com/D-Programming-Language/phobos/pull/742#issuecomment-7687225
and still there is no answer given.
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Денис В. Шеломовский
Denis V. Shelomovskij