[JENKINS-70805] Remove !important from styles in <pre>

[uhafner]

Jenkins should allow plugins to change the fonts in themes or plugins that render pre-formatted text. I'm not sure why the important! suffix has been added here but the console view still renders fine when this suffix will be removed.

For more details please see JENKINS-70805.

Console View Before (Left), After (Right) [Both are identical]:

Source Code View with Prism Plugin Before (Left), After (Right) [Right is fixed, left is broken]:

Testing done

Manual testing by inspecting the console log view and the source code view of the warnings plugin.

Proposed changelog entries

• Align source code text and line numbers in views that render source code with the Prism plugin.

Proposed upgrade guidelines

N/A

Submitter checklist

• The Jira issue, if it exists, is well-described.
• The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the imperative mood (see examples).
  • Fill in the Proposed upgrade guidelines section only if there are breaking changes or changes that may require extra steps from users during upgrade.
• There is automated testing or an explanation as to why this change has no tests.
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• New or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content Security Policy (CSP) directives (see documentation).
• For dependency updates, there are links to external changelogs and, if possible, full differentials.
• For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

@timja
@janfaracik

Maintainer checklist

Before the changes are marked as ready-for-merge:

• There are at least two (2) approvals for the pull request and no outstanding requests for change.
• Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
• Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
• Proper changelog labels are set so that the changelog can be generated automatically.
• If the change needs additional upgrade steps from users, the upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the pull request title (see example).
• If it would make sense to backport the change to LTS, a Jira issue must exist, be a Bug or Improvement, and be labeled as lts-candidate to be considered (see query).

[daniel-beck]

Originally added in @janfaracik's #6259 without explanation.

[janfaracik]

Looking good. Only regression that I've found is the CodeMirror textarea on Script Console no longer has the correct font.

Before this change

After this change

I haven't tried but looks like that could be fixed by applying the properties to .cm-variable in codemirror.less, e.g.

  .cm-variable {
    color: var(--pre-color);
    font-family: var(--font-family-mono);
    font-weight: 500;
    line-height: 1.66;
  }

[github-actions]

Please take a moment and address the merge conflicts of your pull request. Thanks!

[NotMyFault]

Thanks!

[timja]

/label ready-for-merge

---

This PR is now ready for merge, after ~24 hours, we will merge it if there's no negative feedback.

Thanks!