Update doc/providers/security.rst

Take 2 on sorting out the parenthesis in the registration code snippet.
merged branch KodoArkivo/master (PR #591)

This PR was merged into the master branch.

Commits
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ae7daed Update doc/providers/security.rst

Discussion
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Take 2 on sorting out the parenthesis in the registration code snippet.

Take 2 on sorting out the parenthesis in the registration code snippet.