another sms dependency

[kohlhase]

sms generation needs to take into account the following case as well:

\begin{mhview}[frompath=search/en/problem-formulation]{problem-formulation}{search-problem}

example from MathHub/MiKoMH/AI/source/search/en/search-problem
This must make MathHub/MiKoMH/AI/source/search/en/problem-formulation.sms. Similarly, if the topath option is given then .../search-problem.sms must be given (unless -- as in this case -- we are in the file already).

And for the {view} environment as well. There the attributes are loadfrom and loadto.

[lambdaTotoro]

This became irrelevant with the deprecation of the sms format (see #551). Closing.