Edit init_from_rdkit_mol docstring (#414)

Issues: #396

Added additional notes section in the docstring to explain that users
should kekulize their molecule prior to calling the
`init_form_rdkit_mol` method. It also explains the consequences of not
doing so (bond orders changed to integer values).

Co-authored-by: stevenbennett96 <stevenbennettonline@gmail.com>

src/stk/molecular/molecules/building_block.py

@@ -470,7 +470,7 @@ def init_from_file(
             )
         # This remake needs to be here because molecules loaded
         # with rdkit often have issues, because rdkit tries to do
-        # bits of structural analysis like stereocenters. remake
+        # bits of structural analysis like stereocenters. Remake
         # gets rid of all this problematic metadata.
         molecule = remake(cls._init_funcs[extension](path))
 
@@ -490,6 +490,13 @@ def init_from_rdkit_mol(
         """
         Initialize from an :mod:`rdkit` molecule.
 
+        Notes
+        -----
+        For :mod:`rdkit` molecules with non-integer bond orders,
+        such as 1.5, the molecule should be kekulized prior to
+        calling this method. Otherwise, all bond orders will be
+        set to an integer value in the building block.
+
         Parameters
         ----------
         molecule : :class:`rdkit.Mol`