Kernel: Remove useless return value from procfs_get_thread_stack

Kernel/Process.h

@@ -567,7 +567,7 @@ public:
     ErrorOr<void> procfs_get_binary_link(KBufferBuilder& builder) const;
     ErrorOr<void> procfs_get_current_work_directory_link(KBufferBuilder& builder) const;
     mode_t binary_link_required_mode() const;
-    ErrorOr<size_t> procfs_get_thread_stack(ThreadID thread_id, KBufferBuilder& builder) const;
+    ErrorOr<void> procfs_get_thread_stack(ThreadID thread_id, KBufferBuilder& builder) const;
     ErrorOr<void> traverse_stacks_directory(FileSystemID, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const;
     ErrorOr<NonnullRefPtr<Inode>> lookup_stacks_directory(const ProcFS&, StringView name) const;
     ErrorOr<size_t> procfs_get_file_description_link(unsigned fd, KBufferBuilder& builder) const;

Kernel/ProcessSpecificExposed.cpp

@@ -19,12 +19,12 @@
 
 namespace Kernel {
 
-ErrorOr<size_t> Process::procfs_get_thread_stack(ThreadID thread_id, KBufferBuilder& builder) const
+ErrorOr<void> Process::procfs_get_thread_stack(ThreadID thread_id, KBufferBuilder& builder) const
 {
     JsonArraySerializer array { builder };
     auto thread = Thread::from_tid(thread_id);
     if (!thread)
-        return Error::from_errno(ESRCH);
+        return ESRCH;
     bool show_kernel_addresses = Process::current().is_superuser();
     bool kernel_address_added = false;
     for (auto address : Processor::capture_stack_trace(*thread, 1024)) {
@@ -38,8 +38,7 @@ ErrorOr<size_t> Process::procfs_get_thread_stack(ThreadID thread_id, KBufferBuil
     }
 
     array.finish();
-    // FIXME: This return value seems useless.
-    return 0;
+    return {};
 }
 
 ErrorOr<void> Process::traverse_stacks_directory(FileSystemID fsid, Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const