Fix broken links in #3672

[charlottetan]

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What does this PR do?

Improve Repo
Addresses #3672, went through all the links reported in the ticket, several were no longer in the file, some were false positives, some were truly broken and are fixed in this PR

For resources

Description

Why is this valuable (or not)?

How do we know it's really free?

For book lists, is it a book? For course lists, is it a course? etc.

Checklist:

• Not a duplicate
• Included author(s) if appropriate
• Lists are in alphabetical order
• Needed indications added (PDF, access notes, under construction)

[SethFalco]

After you renamed "MySQL Tutorial..." To "MySQL 8.0...", it's position should've changed too since we keep lists in alphabetical order.

Could you just reorder the MySQL section please?

Edit: Alternatively you could rename it back as 8.0 does not appear to be a part of its name. The resource is simply called "MySQL Tutorial".

[charlottetan]

Thanks @SethiPandi! Missed that!

[eshellman]

We really appreciate high quality PRs like this one.