Fix formatting accidentally removed disa_stig_part3.md

[sspencerwire]

• a contributor fixing markdown errors in the past, stripped out the double-space markdown that creates a blank line, this caused this file to be badly formatted.
• reinserted the double-space at end of line for those lines needing it

Author checklist (Completed by original Author)

• Good fit for the Rocky Linux project? Title and Author Metatags inserted ?
• If applicable, steps and instructions have been tested to work
• Initial self-review to fix basic typos and grammar completed

Rocky Documentation checklist (Completed by Rocky team)

• 1st Pass (Document is good fit for project and author checklist completed)
• 2nd Pass (Technical Review - check for technical correctness)
• 3rd Pass (Detailed Editorial Review and Peer Review)
• Final approval (Final Review)

[github-actions]

Test results for 921cf5d:

Number of broken URLs: 2

URL,RESULT,FILENAME
 http://untroubled.org/bcron/,failed,guides/automation/cronie.md
 https://www.ssi.gouv.fr/en/,failed,books/disa_stig/disa_stig_part2.md