fix typo

Signed-off-by: lilinjie <lilinjie@uniontech.com>

Author: uniontech-lilinjie

gssapi/raw/__init__.py

@@ -30,7 +30,7 @@
 are in modules of the form `gssapi.raw.ext_xyz`.
 
 All available functions and classes can be accessed directly from this
-module (`gssapi.raw`) -- it is unneccessary to directly import submodules.
+module (`gssapi.raw`) -- it is unnecessary to directly import submodules.
 """