When using `funm` from linear-algebra package I have noticed a small incompatibility with the corresponding matlab function.

`funm` does not accept as argument the functions `exp`, `log` and `sqrt`.

The reason for that is described in the function's documentation:

## Note that you should not use funm for 'sqrt', 'log' or 'exp'; instead
## use sqrtm, logm and expm as these are more robust.

Yet reading the code this seems to be an outdated comment because if we add them to the set of supported functions then funm will delegate its evaluation to the `thfm` function that supports them (by calling the corresponding sqrtm, logm and expm functions).

So, at least for compatibility, I suggest to add those three functions to the set of supported function since funm already does the right thing and thus I also suggest to remove that comment from the documentation.

I send an attached patch with the proposed trivial changes.