[QualGroup] Add August and September 2025 slides and unify Meeting Materials (#156897)

This patch updates the Qualification WG documentation to:

- Add PDF slide decks for the August and September 2025 sync-up meetings
- Merge the "Meeting Minutes" and "Presentation Slides" sections into a
unified "Meeting Materials" section
- Clarify that agendas and minutes are all published in the Discourse
thread
- Temporarily link to slide files in `llvm/docs/qual-wg/slides/`
- Mention that a future patch will migrate these slide files to the
`llvm-www` repository, once a suitable hosting location is confirmed
with the community (e.g. per discussion with @nikic in
#147196).

---------

Co-authored-by: Wendi Urribarri (Woven by Toyota <[email protected]>

Author: uwendi

llvm/docs/QualGroup.rst

@@ -48,15 +48,25 @@ Participation is open to anyone interested. There are several ways to get involv
 
 We welcome contributors from diverse backgrounds, organizations, and experience levels.
 
-Meeting Minutes
-===============
+Meeting Materials
+=================
+
+Agendas, meeting notes, and presentation slides for the LLVM Qualification Working Group sync-ups
+are shared to ensure transparency and continuity.
+
+Upcoming and past meeting agendas, and meeting minutes are published in a dedicated thread
+on the LLVM Discourse forum: `Meeting Agendas and Minutes <https://discourse.llvm.org/t/llvm-qualification-wg-sync-ups-meeting-minutes/87148>`_ 
 
-Meeting notes for the LLVM Qualification Working Group are published on the 
-LLVM Discourse forum. These notes provide a summary of topics discussed, 
-decisions made, and next steps. 
+Slides used to support discussions during sync-up meetings are stored in LLVM's GitHub repository.
+
+Available slides:
+* `September 2025 <../qual-wg/slides/202509_llvm_qual_wg.pdf>`_
+* `August 2025 <../qual-wg/slides/202508_llvm_qual_wg.pdf>`_
+* `July 2025 <../qual-wg/slides/202507_llvm_qual_wg.pdf>`_
+* (add future entries here)
 
-You can access all minutes here:
-https://discourse.llvm.org/t/llvm-qualification-wg-sync-ups-meeting-minutes/87148
+A future patch will migrate these slide files to the `llvm-www` repository, once
+a suitable hosting location is confirmed with the community.
 
 Contributors
 ============
@@ -65,23 +75,12 @@ The LLVM Qualification Working Group is a collaborative effort involving partici
 from across the LLVM ecosystem. These include community members and industry contributors
 with experience in compiler development, tool qualification, and functional safety.
 
-While contributor names are recorded in the `Meeting Minutes`_ for those who attend 
+While contributor names are recorded in the meeting minutes for those who attend 
 sync-up calls, we also recognize contributions made asynchronously via Discord, GitHub, 
 and other discussion channels.
 
 All forms of constructive participation are valued and acknowledged.
 
-Presentation Slides
-===================
-
-Slides used to support discussions during sync-up meetings are stored in the
- `qual-wg/slides/` directory of the LLVM repository.
-
- Available slides:
-
-* :download:`July 2025 <qual-wg/slides/202507_llvm_qual_wg.pdf>`
-* (add future entries here)
-
 Code of Conduct
 ===============