try_inverse and ownership

[imyxh]

Hi, I noticed in the docs for try_inverse_mut:

If you need to preserve the original matrix regardless of success or failure, consider using Self::try_inverse instead.

But try_inverse takes self, not &self, and consumes the matrix. So, two points:

1. Should the docs be reworded? To me, the implication that try_inverse preserves the original matrix seems to be false. Or is something else meant by "preserved"?
2. Is there a possible performance optimization here, to maketry_inverse not take ownership of the matrix, and thus allow the end-user to avoid .clone()? We still have to allocate memory for the LU decomposition, but we can at least save CPU cycles copying all the values, right?