[docs] Performance docs refactor p.2 (#26791)
* initial edits
* improvements for clarity and flow
* improvements for clarity and flow, removed the repetead section
* removed two docs that had no content
* Revert "removed two docs that had no content"
This reverts commit e98fa2fa0d8e171163f15cb8a04bdada1053543b.
* Apply suggestions from code review
Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
* feedback addressed
* more feedback addressed
* feedback addressed
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Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
