It's mostly a filler word. I've read through each use of it in the code
base and did minor rephrasings when "simply" carried some meaning. The
overwhelming majority of cases, removing it improved the text
significantly. Inspired by #20793.
Closes#20822
Fix new issues found by `proselint`.
Also:
- silence this technical warning:
```
:0: DeprecationWarning: /home/runner/.proselintrc was found instead of a JSON file. Rename to /home/runner/.proselintrc.json.
```
- fix an input filename.
`proselints` fails now if an input file is missing.
Reported-by: Jay Satiro
Bug: https://github.com/curl/curl/pull/15291#issuecomment-2410505100Closes#15293