Handle the TypeVar for format checker callables.

Mostly follows sphinx-doc/sphinx#10785

Author: Julian

docs/api/jsonschema/index.rst

@@ -17,3 +17,6 @@ Package summary
 .. automodule:: jsonschema
    :members:
    :imported-members:
+
+
+.. autodata:: jsonschema._format._F

docs/conf.py

@@ -36,6 +36,33 @@
 
 html_theme = "furo"
 
+# See sphinx-doc/sphinx#10785
+_TYPE_ALIASES = {
+    "jsonschema._format._F",  # format checkers
+}
+
+
+def _resolve_type_aliases(app, env, node, contnode):
+    if (
+        node["refdomain"] == "py"
+        and node["reftype"] == "class"
+        and node["reftarget"] in _TYPE_ALIASES
+    ):
+        return app.env.get_domain("py").resolve_xref(
+            env,
+            node["refdoc"],
+            app.builder,
+            "data",
+            node["reftarget"],
+            node,
+            contnode,
+        )
+
+
+def setup(app):
+    app.connect("missing-reference", _resolve_type_aliases)
+
+
 # = Builders =
 
 doctest_global_setup = """

jsonschema/_format.py

@@ -11,6 +11,7 @@
 from jsonschema.exceptions import FormatError
 
 _FormatCheckCallable = typing.Callable[[object], bool]
+#: A format checker callable.
 _F = typing.TypeVar("_F", bound=_FormatCheckCallable)
 _RaisesType = typing.Union[
     typing.Type[Exception], typing.Tuple[typing.Type[Exception], ...],