DOC: fix a couple typos found by codespell in NEPs

Author: DimitriPapadopoulos

doc/neps/nep-0055-string_dtype.rst

@@ -990,7 +990,7 @@ in the array buffer as a short string.
 
 No matter where it is stored, once a string is initialized it is marked with the
 ``NPY_STRING_INITIALIZED`` flag. This lets us clearly distinguish between an
-unitialized empty string and a string that has been mutated into the empty
+uninitialized empty string and a string that has been mutated into the empty
 string.
 
 The size of the allocation is stored in the arena to allow reuse of the arena

doc/neps/nep-0056-array-api-main-namespace.rst

@@ -302,7 +302,7 @@ three types of behavior rather than two - ``copy=None`` means "copy if needed".
 an exception because they use* ``copy=False`` *explicitly in their copy but a
 copy was previously made anyway, they have to inspect their code and determine
 whether the intent of the code was the old or the new semantics (both seem
-rougly equally likely), and adapt the code as appropriate. We expect most cases
+roughly equally likely), and adapt the code as appropriate. We expect most cases
 to be* ``np.array(..., copy=False)``, *because until a few years ago that had
 lower overhead than* ``np.asarray(...)``. *This was solved though, and*
 ``np.asarray(...)`` *is idiomatic NumPy usage.*