[clang] [clang] Add sections to C++ DR status page (PR #165749)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

The latest look of the table, now wider and without section numbers:

<img width="1627" height="414" alt="image" src="https://github.com/user-attachments/assets/46b8e723-9970-4619-8b96-fb44fd4acd03" />

I noticed that out website's global style forces cell contents to vertically align to the top, even though on my screenshot they are centered. I prefer centered, but I guess I shouldn't fight with site-wide styles in this PR.

https://github.com/llvm/llvm-project/pull/165749