`cabal clean --help` still thinks that `dist` is the default `--builddir`

```
$ cabal-3.14.1.1 clean --help
Clean the package store and remove temporary files.

Usage: cabal-3.14.1.1 new-clean [FLAGS]

Removes all temporary files created during the building process (.hi, .o,
preprocessed sources, etc.) and also empties out the local caches (by
default).

Flags for clean:
...
--builddir=DIR The directory where Cabal puts generated build
files (default dist)
```
- That should be `dist-newstyle` rather than `dist`, I suppose.
- `new-clean` should be just `clean` (correct would also be `v2-clean` but the `v2` prefix is generally not printed).

I also think it would be good that the help text "Removes all temporary files..." would add the clarification "in DIR (see --builddir below)".

Start by locating the Cabal help text for the clean command and its --builddir flag, then run cabal-3.14.1.1 clean --help to compare the current output with the issue. Done means the default reads dist-newstyle, the usage line uses clean rather than new-clean, and the temporary-files description refers to the selected build directory.

Written by the indexing model from the issue text.