interpreter: use typed_kwargs for executable's "implib" keyword argument

mesonbuild/interpreter/interpreter.py

@@ -1806,7 +1806,6 @@ class Interpreter(InterpreterBase, HoldableObject):
     def func_disabler(self, node, args, kwargs):
         return Disabler()
 
-    @FeatureNewKwargs('executable', '0.42.0', ['implib'])
     @permittedKwargs(build.known_exe_kwargs)
     @typed_pos_args('executable', str, varargs=SOURCES_VARARGS)
     @typed_kwargs('executable', *EXECUTABLE_KWS, allow_unknown=True)

mesonbuild/interpreter/kwargs.py

@@ -342,6 +342,7 @@ class Executable(_BuildTarget):
 
     export_dynamic: bool
     gui_app: T.Optional[bool]
+    implib: T.Optional[T.Union[str, bool]]
     pie: T.Optional[bool]
     vs_module_defs: T.Optional[T.Union[str, File, build.CustomTarget, build.CustomTargetIndex]]
     win_subsystem: T.Optional[str]

mesonbuild/interpreter/type_checking.py

@@ -590,6 +590,7 @@ _DARWIN_VERSIONS_KW: KwargInfo[T.List[T.Union[str, int]]] = KwargInfo(
 _EXCLUSIVE_EXECUTABLE_KWS: T.List[KwargInfo] = [
     KwargInfo('export_dynamic', bool, default=False, since='0.45.0'),
     KwargInfo('gui_app', (bool, NoneType), deprecated='0.56.0', deprecated_message="Use 'win_subsystem' instead"),
+    KwargInfo('implib', (bool, str, NoneType), since='0.42.0'),
     KwargInfo('pie', (bool, NoneType)),
     KwargInfo(
         'win_subsystem',