doc: use dnf5 for Fedora documentation tools

[SanjayrajN-in]

In newer Fedora versions the package manager CLI is dnf5 instead of dnf, so commands using dnf may fail. This change updates the Fedora documentation tools instructions to use dnf5 and mentions that some systems may still use dnf.

[github-actions]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[str4t0m]

Thanks for the PR.
To the best of my knowledge, on Fedora installations >= 41 usr/bin/dnf links to usr/bin/dnf5, and there is no plan to change that. Could you clarify if you have faced any issue or why you would prefer to document dnf5 explicitly?