chore: rename the private method

Author: stevenhua0320

src/diffpy/srfit/fitbase/profilegenerator.py

@@ -163,14 +163,14 @@ def set_profile(self, profile):
             will store the calculated signal.
         """
         if self.profile is not None:
-            self.profile.removeObserver(self._on_profile_changed)
+            self.profile.removeObserver(self._on_profile_update)
 
         self.profile = profile
-        self.profile.addObserver(self._on_profile_changed)
-        self._on_profile_changed(other=(self,))
+        self.profile.addObserver(self._on_profile_update)
+        self._on_profile_update(other=(self,))
         return
 
-    def _on_profile_changed(self, other=()):
+    def _on_profile_update(self, other=()):
         if self.profile is not None:
             self.meta.update(self.profile.meta)
             self.processMetaData()