Clarify what the "date" filter takes as parameter

Clarify what the "date" filter takes as parameter.

I went through Twig/Extension/Core.php to figure what's happening. I haven't verified that I'm actually correct, but it looks like I am.
merged branch Uplink03/patch-1 (PR #1180)

This PR was merged into the master branch.

Discussion
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Clarify what the "date" filter takes as parameter

Clarify what the "date" filter takes as parameter.

I went through Twig/Extension/Core.php to figure what's happening. I haven't verified that I'm actually correct, but it looks like I am.

Commits
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744ad32 Clarify what the "date" filter takes as parameter
fixed CS