fix: terminate fileworker and watchdog when pipe is closed

Author: mhuisi

src/Lean/Server/FileWorker.lean

@@ -1098,5 +1098,7 @@ def workerMain (opts : Options) : IO UInt32 := do
   catch err =>
     e.putStrLn err.toString
     IO.Process.forceExit 1 -- Terminate all tasks of this process
+  finally
+    IO.Process.forceExit (α := UInt32) 1
 
 end Lean.Server.FileWorker

src/Lean/Server/Watchdog.lean

@@ -1809,5 +1809,7 @@ def watchdogMain (args : List String) : IO UInt32 := do
   catch err =>
     e.putStrLn s!"Watchdog error: {err}"
     IO.Process.forceExit 1 -- Terminate all tasks of this process
+  finally
+    IO.Process.forceExit (α := UInt32) 1
 
 end Lean.Server.Watchdog