Knowledge base: add "callout" blocks (info / tip / warning / danger) to the article editor

[billtemate]

GLPI 12 ships a brand-new TipTap-based editor for knowledge base articles, with a / slash menu offering headings, lists, quote, code block, table, divider, image and video. One block type that is missing (and that has become a de-facto standard in every documentation tool ) is the callout (also called admonition, panel or info box): a highlighted block with an icon and a colour, used to draw the reader's attention to a note, a tip, a warning or a critical point.

Examples of the same concept elsewhere: Confluence panels (info/note/success/warning/error), Notion callouts, GitHub-flavoured Markdown alerts (> [!NOTE], > [!WARNING]…), MkDocs/Docusaurus admonitions, Obsidian callouts.

Note

For example, this one.

Warning

Or this for a warning before make specifics actions...

Why it matters

Procedural documentation (the core use case of the GLPI knowledge base: how-tos, runbooks, FAQs for the helpdesk) relies heavily on "⚠️ Before you start…" / "💡 Tip" / "🛑 Never do X" blocks. Today authors either misuse the quote block, or paste coloured tables, which is fragile and inconsistent (see also issue glpi-project/glpi#25020 about blockquotes being used for long texts).
Teams that maintain procedural documentation in other tools (Confluence, Notion, wikis…) and would like to consolidate it into the GLPI knowledge base currently cannot migrate such pages without losing this structure.
Accessibility: a semantic block with a visible label ("Warning") is better than colour-only formatting.

Proposal (kept minimal on purpose)

One callout block available from the / slash menu and the bubble menu, with 4 variants: info, success/tip, warning, danger.
Rendered as a coloured left border + background tint + a Tabler icon (already bundled in GLPI), consistent with the existing Tabler alert styles used elsewhere in the UI, with dark theme support.
Stored as plain HTML (

…

), which the current sanitizer already accepts, so no database change; the block simply needs a TipTap node so it survives re-editing.
No nesting, no custom colours, no custom icons: 4 fixed variants only.

Alternative

If this is considered out of scope for core, an official extension point allowing plugins to register TipTap extensions in the knowledge base editor would let the community provide it as a plugin.