[docs-scanner] SLES unavailability not explained in platform table

[docker-agent]

File: content/manuals/engine/install/_index.md

Issue

The installation index page shows SLES in the platform support table with an ❌ symbol but provides no explanation:

| [SLES](sles.md)                                |                |                 |              |         |  ❌   |

The linked sles.md page explains that Docker Engine packages are no longer available for SLES s390x, but a reader looking at the table has no way to know this without clicking through. The ❌ symbol appears in the s390x column, but the page title "SLES (s390x)" and the content make clear this is about SLES on s390x specifically, not SLES in general.

Why this matters

Users scanning the platform table to determine if their platform is supported will see the ❌ and may assume SLES is completely unsupported, when in fact the issue is specific to the s390x architecture. The table provides no context about what the ❌ means or why it's there.

Suggested fix

Either:

1. Add a footnote or note explaining that SLES s390x packages are no longer available (with a link to the SLES page for details), or
2. Update the table row to make it clearer this is architecture-specific: SLES (s390x only) or similar, or
3. Remove the SLES row from the table entirely if it's not a supported platform

The current presentation creates confusion about the scope of the unavailability.

---

Found by nightly documentation quality scanner