docs: add user guide for GNOME's screenshot application

[CBID2]

Description

For my final RSOD contribution, I wrote a user guide for GNOME's Screenshot application

Note

I also revised the installation section of the Decibels user guide

Issue

Relates to #2161

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)

[CBID2]

fix metadata

[CBID2]

Hi @sspencerwire. Can you review and merge this please?

[CBID2]

fix

[CBID2]

Can you approve it again @sspencerwire?

[github-actions]

Test results for c8f0273:

Number of broken URLs: 3

URL,RESULT,FILENAME
 http://www.example.org/foo.txt,failed,books/web_services/052-load-balancer-proxies-varnish.md
 http://developer.download.nvidia/compute/cuda/repos/rhel9/$,failed,desktop/display/installing_nvidia_gpu_drivers.md
 https://azuremarketplace.microsoft.com/en-us/marketplace/apps/resf.rockylinux-aarch64,failed,guides/cloud/migration-to-new-azure-images.md