Optimize the diff text when there's no change

[ekohl]

If a PR doens't generate a diff (like this change) then the message shouldn't link to any diffs. By making this message explicit it makes reviewing a bit easier.

• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8)
• Foreman 3.8/Katello 4.10
• Foreman 3.7/Katello 4.9 (Satellite 6.14)
• Foreman 3.6/Katello 4.8
• Foreman 3.5/Katello 4.7 (Satellite 6.13; orcharhino 6.6/6.7)
• Foreman 3.4/Katello 4.6 (EL8 only)
• Foreman 3.3/Katello 4.5 on EL7 & EL8 (Satellite 6.12 on EL8 only; orcharhino 6.4/6.5 on EL8 only)
• We do not accept PRs for Foreman older than 3.3.

[github-actions]

The PR preview for 1df8a46 is available at theforeman-foreman-documentation-preview-pr-3036.surge.sh

The following output files are affected by this PR:

show diff

show diff as HTML

[ekohl]

The following output files are affected by this PR:

show diff

show diff as HTML

This suggests it's not working as intended, but the workflow runs after deploy finished and uses the defintiion from core rather than the PR.

[Lennonka]

Lovely idea. Not sure about the implementation, though :)

[Lennonka]

Suggested change

	if [[ -f diff.patch ]] ; theni
	if [[ -f diff.patch ]] ; then

[Lennonka]

Suggested change

	if [[ -f diff.html ]] ; theni
	if [[ -f diff.html ]] ; then

[Lennonka]

Suggested change

	if [[ -f diff.txt ]] ; then
	if [ -f diff.txt ] ; then

AFAIK, [[ ]] is for conditional command execution, whereas [ ] is test, which is probably what you're trying to do.
If you're using [[ ]] with an intent, can you please explain why is it better here than [ ] (test)?

[ekohl]

When testing the implementation appeared to have an issue, so I need to dive into it a bit more. Though perhaps that was in the other repo I was playing with