Correct and update several optparse types (#4897)

The first positional argument to HelpFormatter.format_option() and
HelpFormatter.format_option_strings() is a Option instance, not an
OptionParser.

Added some attributes to the Option class:

- callback
- callback_args
- callback_kwargs
- help
- metavar

The OptionParser.option_groups attribute is a list of OptionGroup
instances, not OptionParser instances.

The method OptionParser.add_option_group() returns a OptionGroup
instance (the one created/added), not an OptionParser instance.

stdlib/2and3/optparse.pyi

@@ -59,8 +59,8 @@ class HelpFormatter:
     def format_description(self, description: _Text) -> _Text: ...
     def format_epilog(self, epilog: _Text) -> _Text: ...
     def format_heading(self, heading: Any) -> _Text: ...
-    def format_option(self, option: OptionParser) -> _Text: ...
-    def format_option_strings(self, option: OptionParser) -> _Text: ...
+    def format_option(self, option: Option) -> _Text: ...
+    def format_option_strings(self, option: Option) -> _Text: ...
     def format_usage(self, usage: Any) -> _Text: ...
     def indent(self) -> None: ...
     def set_long_opt_delimiter(self, delim: _Text) -> None: ...
@@ -98,6 +98,11 @@ class Option:
     dest: Optional[_Text]
     nargs: int
     type: Any
+    callback: Optional[Callable[..., Any]]
+    callback_args: Optional[Tuple[Any, ...]]
+    callback_kwargs: Optional[Dict[_Text, Any]]
+    help: Optional[_Text]
+    metavar: Optional[_Text]
     def __init__(self, *opts: Optional[_Text], **attrs: Any) -> None: ...
     def _check_action(self) -> None: ...
     def _check_callback(self) -> None: ...
@@ -109,8 +114,8 @@ class Option:
     def _check_type(self) -> None: ...
     def _set_attrs(self, attrs: Dict[_Text, Any]) -> None: ...
     def _set_opt_strings(self, opts: Iterable[_Text]) -> None: ...
-    def check_value(self, opt: Any, value: Any) -> Any: ...
-    def convert_value(self, opt: Any, value: Any) -> Any: ...
+    def check_value(self, opt: _Text, value: Any) -> Any: ...
+    def convert_value(self, opt: _Text, value: Any) -> Any: ...
     def get_opt_string(self) -> _Text: ...
     def process(self, opt: Any, value: Any, values: Any, parser: OptionParser) -> int: ...
     def take_action(self, action: _Text, dest: _Text, opt: Any, value: Any, values: Any, parser: OptionParser) -> int: ...
@@ -169,7 +174,7 @@ class OptionParser(OptionContainer):
     epilog: Optional[_Text]
     formatter: HelpFormatter
     largs: Optional[List[_Text]]
-    option_groups: List[OptionParser]
+    option_groups: List[OptionGroup]
     option_list: List[Option]
     process_default_values: Any
     prog: Optional[_Text]
@@ -203,9 +208,9 @@ class OptionParser(OptionContainer):
     def _process_long_opt(self, rargs: List[Any], values: Any) -> None: ...
     def _process_short_opts(self, rargs: List[Any], values: Any) -> None: ...
     @overload
-    def add_option_group(self, __opt_group: OptionGroup) -> OptionParser: ...
+    def add_option_group(self, __opt_group: OptionGroup) -> OptionGroup: ...
     @overload
-    def add_option_group(self, *args: Any, **kwargs: Any) -> OptionParser: ...
+    def add_option_group(self, *args: Any, **kwargs: Any) -> OptionGroup: ...
     def check_values(self, values: Values, args: List[_Text]) -> Tuple[Values, List[_Text]]: ...
     def disable_interspersed_args(self) -> None: ...
     def enable_interspersed_args(self) -> None: ...