Docs: Move SAST reference table below concepts and tasks

What does this MR do?

What: Within the SAST analyzers page, move the reference table below concepts and tasks without changing its contents.

Why: We often link to specific sections. However, if a user is browsing the documentation or lands on the overall analyzers page, I want to make sure that they see the concepts and tasks for customization and Semgrep transition.

I fear they won't notice that this content is below the large analyzers table. The table itself is both wide and tall, and it can cover a full screen (and even overlap with the table of contents links) at certain screen sizes.

Screenshot of overlapping table and TOC

Related issues

N/A

Author's checklist

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• ~"frontend"
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Reviewer's checklist

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    • The headings should be something you'd do a Google search for. Instead of Default behavior, say something like Default behavior when you close an issue.
    • The headings (other than the page title) should be active. Instead of Configuring GDK, say something like Configure GDK.
    • Any task steps should be written as a numbered list.
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