using doc-forge (#1)

Reviewed-on: #1
Co-authored-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>
Co-committed-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>

openapi_first/errors.pyi

@@ -0,0 +1,6 @@
+from typing import Optional
+
+class OpenAPIFirstError(Exception): ...
+
+class MissingOperationHandler(OpenAPIFirstError):
+    def __init__(self, *, path: str, method: str, operation_id: Optional[str] = ...) -> None: ...