Documentation for predefined observables.

[ALF-Import-Bot]

In GitLab by @fassaad on May 19, 2025, 12:39 UTC:

In the documentation on predefined observables Sec 8.4 we should make it very clear that there are two types of predefined observables.

1. Those where the Observable Obs is passed in the argument list and the incremental count Obs%N = Obs%N +1 and Ops%Ave_sign = Obs%Ave_sign + Real(ZS) is done automatically 8and should not be redone)

2. Those where we call a function, and in which the value of the observable is returned. There you should the incremental count manually.

I will add this at the beginning of section 8.4, provided that there are no objections.

Migrated from GitLab: https://git.physik.uni-wuerzburg.de/ALF/ALF/-/issues/310