Track down where Material.density is called more exactly

Using traceback, we can find the thing that called `Material.density`
when the material is attached to a `Component`. This information,
specifically the file name and line number, is used in the warning
message. The file name and line number is used as the label in the
warning so multiple locations that invoke this behavior will show up
as one logged message. But their number of invocations will also be
counted.

armi/materials/material.py

@@ -18,6 +18,7 @@
 Most temperatures may be specified in either K or C and the functions will convert for you.
 """
 import functools
+import traceback
 import warnings
 
 from scipy.optimize import fsolve
@@ -45,11 +46,15 @@ def parentAwareDensityRedirect(f):
     @functools.wraps(f)
     def inner(self: "Material", *args, **kwargs) -> float:
         if self.parent is not None:
+            stack = traceback.extract_stack()
+            # last entry is here, second to last is what called this
+            caller = stack[-2]
+            label = f"Found call to Material.density in {caller.filename} at line {caller.lineno}"
             runLog.warning(
-                "Calling Material.density when attached to a Component is "
-                "undesirable and can introduce subtle differences. Prefer "
-                "directly calling the parent component's density method. "
-                f"Found on {self=} attached to {self.parent=}",
+                f"{label}. Calls to Material.density when attached to a component have the potential to induce "
+                "subtle differences as Component.density and Material.density can diverge.",
+                single=True,
+                label=label,
             )
         return f(self, *args, **kwargs)