move clear() method out of base class

...so that dict.clear() and list.clear()
can have different docstrings.

src/sanest/sanest.py

@@ -436,12 +436,6 @@ def __delitem__(self, path_like):
         except LookupError as exc:
             raise typeof(exc)(path) from None
 
-    def clear(self):
-        """
-        Clear this container; like ``dict.clear()`` and ``list.clear()``.
-        """
-        self._data.clear()
-
     def __eq__(self, other):
         if self is other:
             return True
@@ -712,6 +706,12 @@ def popitem(self, *, type=None):
         value = self.pop(key, type=type)
         return key, value
 
+    def clear(self):
+        """
+        Like ``dict.clear()``.
+        """
+        self._data.clear()
+
     def keys(self):
         """
         Like ``dict.keys()``; returns a dictionary view.
@@ -1041,6 +1041,12 @@ def remove(self, value, *, type=None):
         except ValueError:
             raise ValueError("{!r} is not in list".format(value)) from None
 
+    def clear(self):
+        """
+        Like ``list.clear()``.
+        """
+        self._data.clear()
+
     def reverse(self):
         """
         Like ``list.reverse()``.