STY: Fix typos found by codespell

Author: DimitriPapadopoulos

nipype/interfaces/base/traits_extension.py

@@ -58,7 +58,7 @@
 Undefined deep and down in traits/ui/wx/list_editor.py it checks for
 the len() of the elements of the list.  The _Undefined class in traits
 does not define the __len__ method and would error.  I tried defining
-our own Undefined and even sublassing Undefined, but both of those
+our own Undefined and even subclassing Undefined, but both of those
 failed with a TraitError in our initializer when we assign the
 Undefined to the inputs because of an incompatible type:
 

nipype/interfaces/semtools/brains/utilities.py

@@ -53,7 +53,7 @@ class HistogramMatchingFilterInputSpec(CommandLineInputSpec):
     )
     histogramAlgorithm = traits.Enum(
         "OtsuHistogramMatching",
-        desc=" histogram algrithm selection",
+        desc=" histogram algorithm selection",
         argstr="--histogramAlgorithm %s",
     )
     verbose = traits.Bool(