gh-113317: Argument Clinic: remove global clinic instance (#115517)

Tools/clinic/clinic.py

@@ -277,7 +277,7 @@ def __init__(self, filename: str) -> None:
     @abc.abstractmethod
     def render(
             self,
-            clinic: Clinic | None,
+            clinic: Clinic,
             signatures: Iterable[Module | Class | Function]
     ) -> str:
         ...
@@ -630,7 +630,7 @@ def parse_line(self, line: str) -> None:
 
     def render(
             self,
-            clinic: Clinic | None,
+            clinic: Clinic,
             signatures: Iterable[Module | Class | Function]
     ) -> str:
         function = None
@@ -1584,7 +1584,7 @@ def render_option_group_parsing(
 
     def render_function(
             self,
-            clinic: Clinic | None,
+            clinic: Clinic,
             f: Function | None
     ) -> str:
         if f is None or clinic is None:
@@ -2220,7 +2220,6 @@ def __init__(self, clinic: Clinic) -> None: ...
     def parse(self, block: Block) -> None: ...
 
 
-clinic: Clinic | None = None
 class Clinic:
 
     presets_text = """
@@ -2345,9 +2344,6 @@ def __init__(
             assert name in self.destination_buffers
             preset[name] = buffer
 
-        global clinic
-        clinic = self
-
     def add_include(self, name: str, reason: str,
                     *, condition: str | None = None) -> None:
         try: