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]
In Octave ≤ 5, it was impossible to take a function handle for a function in a
package (“+” folder). This bug has been fixed in Octave 6, so we can use the
same codepath as MATLAB in that case. See
https://savannah.gnu.org/bugs/index.php?46659