fix doc strings

hoomd_organics/library/surfaces.py

@@ -5,16 +5,16 @@
 
 
 class Graphene(Compound):
-    """Creates a rectangular graphene layer or multiple layers.
+    """Create a rectangular graphene layer or multiple layers.
 
     Parameters
     ----------
     x_repeat : int, required
-        Number of times to repeat graphene lattice in the x-direciton
+        Number of times to repeat graphene lattice in the x-direciton.
     y_repeat: int, required
-        Number of times to repeat graphene lattice in the y-direciton
+        Number of times to repeat graphene lattice in the y-direciton.
     n_layers: int, optional, default 1
-        Number of times to repeat the complete layer in the normal direction
+        Number of times to repeat the complete layer in the normal direction.
     periodicity : tuple of bools, length=3, optional, default=(True, True, False) # noqa: E501
         Whether the Compound is periodic in the x, y, and z directions.
         If None is provided, the periodicity is set to `(False, False, False)`
@@ -23,7 +23,7 @@ class Graphene(Compound):
     Notes
     -----
     To create bonds along periodic boundaries of the layers in the x and y
-    directions, set periodicity to (True, True, False)
+    directions, set `periodicity = (True, True, False)`
 
     """