Update ALS11012RSoXSLoader.py dark pedestal

Added proper dark subtraction code. Previous version had
img = (img - darkimg + self.dark_pedestal)/corr, which permanently adds the value of the dark pedestal to your data. Corrected version adds the dark pedestal first, performs the subtraction and correction, and then takes the pedestal back out.

Interestingly, I think that this code used to be correct.

Author: cbishop4

src/PyHyperScattering/ALS11012RSoXSLoader.py

@@ -166,7 +166,9 @@ def loadSingleImage(self,filepath,coords=None,return_q=False,**kwargs):
                 warnings.warn(f"Could not find a dark image with exposure time {headerdict['EXPOSURE']}.  Using zeros.",stacklevel=2)
                 darkimg = np.zeros_like(img)
 
-            img = (img-darkimg+self.dark_pedestal)/corr
+            img += self.dark_pedestal
+            img = (img - darkimg) / corr
+            img -= self.dark_pedestal / corr
 
         # now, match up the dims and coords
         if return_q: