See commit 2983aafa for the rationale.

(cherry picked from commit 2b2376c9)

In Sphinx 8, returned filesystem path objects are no longer extended to have
implicit string conversion methods. The conversion to a string must now be made
explicitly.

See this entry in the changelog for Sphinx 8.0:

 #12650, #12686, #12690: Extend the deprecation for string methods on
 :py:class:`~pathlib.Path` objects to Sphinx 9. Use :py:func:`os.fspath` to
 convert :py:class:`~pathlib.Path` objects to strings, or
 :py:class:`~pathlib.Path`'s methods to work with path objects. Patch by Adam
 Turner.

(cherry picked from commit 2983aafa)

Closes: #1707
(cherry picked from commit 85c637d3)

It is now supported by the MATLAB editor (as of R2022a).

The old ASCII notation is left in some files that we copy as-is from other
sources (e.g. in the contrib/ and m4/ subdirectories).

The particles submodule is not updated at this point, because it is in an
inconsistent state.

[skip ci]

sphinx.locale.l_ has been deprecated since Sphinx 1.8, and removed in Sphinx 3.

Use sphinx.locale._ instead.

This reverts commit 6d516c39.

The method `desc_addname` adds arguments to the name of the node, and hence does not allow for line breaks. In the case of Dynare commands we don't run into a problem with this but we run into this problem with longer MATLAB/Octave commands.

For Dynare commands, we don't run into the problem with commands running over the page width as we use placeholders like `OPTIONS` since the order of the parameters passed to a command is irrelevant

For MATLAB/Octave commands, the order of parameters passed to a function is important, hence we cannot use a placeholder such as `OPTIONS`

closes #1688

- remove trailing whitespace
- replace tabs with spaces as per PEP guidelines