[json] Add default value for strict param to scanstring (#14441)

Author: donBarbos

stdlib/_json.pyi

@@ -48,4 +48,4 @@ class make_scanner:
 
 def encode_basestring(s: str, /) -> str: ...
 def encode_basestring_ascii(s: str, /) -> str: ...
-def scanstring(string: str, end: int, strict: bool = ...) -> tuple[str, int]: ...
+def scanstring(string: str, end: int, strict: bool = True) -> tuple[str, int]: ...