Fix docs (Process.open() -> Process(); remove trailing whitespace

mem_edit/abstract.py

@@ -33,7 +33,7 @@ class Process(metaclass=ABCMeta):
       and use it to read and write to memory. Once you are done with the process,
       use .close() to free up the process for access by other debuggers etc.
 
-        p = Process.open(1239)
+        p = Process(1239)
         p.close()
 
     To read/write to memory, first create a buffer using ctypes: