Unrolled build for rust-lang#134815

Rollup merge of rust-lang#134815 - 9names:sort_platform_md_targets, r=jieyouxu

Sort triples by name in platform_support.md

When looking for riscv32emc support, I missed it at first because it was at the end of the tier3 target list [here](https://doc.rust-lang.org/rustc/platform-support.html#tier-3). These lists are *mostly* dictionary sorted so I assumed it should be near the riscv32i* targets.

This PR puts all targets back in dictionary order. There were only a few outside of tier3.

I ended up writing a small program to sort them because I did not trust myself to do it manually, but I stopped short of fully automating it.
I have manually reviewed the output to confirm it still has the same number of entries, and that the changed values do follow the ordering I would expect.

For folks who would prefer to review code than manual textual changes, the sorting program (including inputs) is [here.](https://github.com/9names/platform_sort_arch/blob/main/src/main.rs)