remove redundant warning and move the note to documentation

Author: skim0119

docs/api/contact.rst

@@ -8,6 +8,12 @@ Contact
 Description
 -----------
 
+.. note::
+   (CAUTION)
+   The contact is recommended to be added at last. This is because contact forces often includes
+   friction that may depend on other normal forces and contraints to be calculated accurately.
+   Be careful on the order of adding interactions.
+
 .. rubric:: Available Contact Classes
 
 .. autosummary::

elastica/modules/contact.py

@@ -26,8 +26,7 @@
 logger = logging.getLogger(__name__)
 
 
-def warnings() -> None:
-    logger.warning("Contact features should be instantiated lastly.")
+
 
 
 class Contact:
@@ -97,8 +96,7 @@ def _finalize_contact(self: ContactedSystemCollectionProtocol) -> None:
 
             self._feature_group_synchronize.add_operators(contact, [func])
 
-            if not self._feature_group_synchronize.is_last(contact):
-                warnings()
+
 
         self._contacts = []
         del self._contacts