DOC: combine regressions in section in v1.0.1 whatsnew
Similarly how we did it for 0.24.x, gathering all regressions in the first section of the whatsnew (as those are the most important part of 1.0.1)

cc @TomAugspurger 
Given that there is not much remaining in the "Bug fixes" section, I can probably remove the subtitles there? > I can probably remove the subtitles there?

Agreed. This will cause merge conflicts with outstanding PRs. What order do you want to merge these in? I can fixup conflicts later here, or also help fixing conflicts in the other PRs. Doesn't matter really to me Let's just merge this since it's already passing. Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
$ git checkout 1.0.x
$ git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
$ git cherry-pick -m1 a9d24502f50045456fe94abb91b867318fcaf54a
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
$ git commit -am 'Backport PR #31607: DOC: combine regressions in section in v1.0.1 whatsnew'
```

4. Push to a named branch :

```
git push YOURFORK 1.0.x:auto-backport-of-pr-31607-on-1.0.x
```

5. Create a PR against branch 1.0.x, I would have named this PR:

> "Backport PR #31607 on branch 1.0.x"

And apply the correct labels and milestones.

Congratulation you did some good work ! Hopefully your backport PR will be tested by the continuous integration and merged soon!

If these instruction are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                