Change link on security index page to use cleaner grammar. (#6784)
Change link on security index page to use cleaner grammar. (#6784)

* Change link on security index page to use cleaner grammar.

This also change the focus to `HTTPS` (an abbreviation that is often used) instead of "Secure HTTP" (which is not quite its formal name, and isn't used as often).

* Clean up language on landing page

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