fix: ensure iter_methods is a generator and fix anyio devnull usage

Author: observerw

src/lsp_client/protocol/capability.py

@@ -20,6 +20,8 @@ def iter_methods(cls) -> Iterator[str]:
         LSP methods associated with this capability.
         """
 
+        yield from ()
+
     @classmethod
     def check_server_capability(cls, cap: lsp_type.ServerCapabilities) -> None:
         """

src/lsp_client/server/container.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import subprocess
 from collections.abc import AsyncGenerator
 from contextlib import asynccontextmanager
 from pathlib import Path
@@ -197,8 +198,8 @@ async def check_availability(self) -> None:
         try:
             await anyio.run_process(
                 [self.backend, "pull", self.image],
-                stdout=anyio.streams.devnull.DevnullStream(),
-                stderr=anyio.streams.devnull.DevnullStream(),
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
             )
         except anyio.ProcessError as e:
             raise RuntimeError(