PyYAML: fix yaml.add_foo() functions (#5828)

Added / modified types for the following functions:
- `add_implicit_resolver(...)`
- `add_path_resolver(...)`
- `add_constructor(...)`
- `add_multi_constructor(...)`
- `add_representer(...)`
- `add_multi_representer(...)`

* Remove yaml.add_constructor from allowlist

* Use TypeVars and overloads

stubs/PyYAML/@tests/stubtest_allowlist.txt

@@ -5,7 +5,6 @@ yaml.CDumper.__init__
 yaml.CEmitter
 yaml.CParser
 yaml.YAMLObjectMetaclass.__init__
-yaml.add_constructor
 yaml.constructor.FullConstructor.set_python_instance_state
 yaml.cyaml.CBaseDumper.__init__
 yaml.cyaml.CDangerDumper