Various doc fixes

Fix a =head1 section name
Fix a typo in POD label
Remove a spurious =back
Add a missing blank line
Avoid 'legacy' -- use 'deprecated' if still needed if we cannot just reword.
Always do strict checking
Do not warn about missing "RETURN VALUES" unless -s is set.
Change OpenSSL version 1.1 -> 1.1.0

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3830)