Removed unneeded line (#3241)

* Removed unneeded line

I guess it's a copy/paste left-over from `meta_dir`.

* Added towncrier doc

The tests complained about the missing changelog, so I added it. I hope I got it right as I was a bit confused about the towncrier dir being empty apart from a template file.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update and rename 3241.doc to 3241.doc.rst

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/changelog/3241.doc.rst

@@ -0,0 +1 @@
+Removed unused line from the 'fresh_subprocess' documentation.

docs/config.rst

@@ -802,7 +802,6 @@ Python virtual environment packaging
    A flag controlling if each call to the build backend should be done in a fresh subprocess or not (especially older
    build backends such as ``setuptools`` might require this to discover newly provisioned dependencies).
 
-   Directory where to put the project metadata files.
 
 Pip installer
 ~~~~~~~~~~~~~