[3.7] bpo-36799: Fix typo in ctypes.rst (GH-13104) (GH-13341)

[3.7] bpo-36799: Fix typo in ctypes.rst (GH-13104) (GH-13341) · python/cpython@4fd7f56

Original file line number	Diff line number	Diff line change
`@@ -2365,7 +2365,7 @@ other data types containing pointer type fields.`
`2365`	`2365`	and so on). Later assignments to the :attr:`_fields_` class variable will
`2366`	`2366`	`raise an AttributeError.`
`2367`	`2367`
`2368`		`- It is possible to defined sub-subclasses of structure types, they inherit`
	`2368`	`+ It is possible to define sub-subclasses of structure types, they inherit`
`2369`	`2369`	the fields of the base class plus the :attr:`_fields_` defined in the
`2370`	`2370`	`sub-subclass, if any.`
`2371`	`2371`
`@@ -2413,7 +2413,7 @@ other data types containing pointer type fields.`
`2413`	`2413`	`td.lptdesc = POINTER(some_type)`
`2414`	`2414`	`td.u.lptdesc = POINTER(some_type)`
`2415`	`2415`
`2416`		`- It is possible to defined sub-subclasses of structures, they inherit the`
	`2416`	`+ It is possible to define sub-subclasses of structures, they inherit the`
`2417`	`2417`	`fields of the base class. If the subclass definition has a separate`
`2418`	`2418`	:attr:`_fields_` variable, the fields specified in this are appended to the
`2419`	`2419`	`fields of the base class.`