Immediately resolve complement operators for regions

[paulromano]

Description

This PR changes how the the ~ operator works on regions. By implementing the __invert__ method on the Intersection and Union classes, De Morgan's laws are always immediately applied, which means that you won't end up with ~ inside an XML file.

Along with this change, I've simplified the handling of the unary - and + operators on some composite surfaces. For example, for XConeOneSided the __neg__ and __pos__ methods were both implemented. However, CompositeSurface has a default __pos__ method that just takes the complement of whatever __neg__ returns. With the improvement in how complements are handled, this means that we don't need to implement __pos__ for composite surfaces and we still end up with an expression that doesn't have ~ in it.

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[shimwell]

def test_filter_mesh_translations(model): is failing with this error

 Input differences:
--- inputs_true.dat
+++ inputs_test.dat
@@ -12,7 +12,7 @@
   </materials>
   <geometry>
     <cell id="1" material="1" region="1 -2 3 -4 10 -9" universe="1"/>
-    <cell id="2" material="2" region="~(1 -2 3 -4) (5 -6 7 -8) 10 -9" universe="1"/>
+    <cell id="2" material="2" region="(-1 | 2 | -3 | 4) (5 -6 7 -8) 10 -9" universe="1"/>

Perhaps this is just a case of updating the dat file

[paulromano]

@shimwell Yes, looks like I missed that one update. It should be fixed now.

[pshriwise]

Great idea @paulromano! Much easier to handle this in Python than with the current C++ algorithm. I suppose we can't do away with the C++ version for a bit, but I think roundtripping the XML through the Python interface should do the trick for users trying to update old files when the time comes.