Kernel: Rename File::{before_removing => will_be_destroyed}

This will allow File and it's descendants to use RefCounted instead of
having a custom implementation of unref. (Since RefCounted calls
will_be_destroyed automatically)

This commit also removes an erroneous call to `before_removing` in
AHCIPort, this is a duplicate call, as the only reference to the device
is immediately dropped following the call, which in turns calls
`before_removing` via File::unref.

Kernel/Devices/Device.cpp

@@ -131,7 +131,7 @@ void Device::after_inserting()
     });
 }
 
-void Device::before_removing()
+void Device::will_be_destroyed()
 {
     VERIFY(m_sysfs_component);
     SysFSComponentRegistry::the().devices_list().with_exclusive([&](auto& list) -> void {

Kernel/Devices/Device.h

@@ -47,7 +47,7 @@ public:
     GroupID gid() const { return m_gid; }
 
     virtual bool is_device() const override { return true; }
-    virtual void before_removing() override;
+    virtual void will_be_destroyed() override;
     virtual void after_inserting();
     void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
 

Kernel/FileSystem/File.cpp

@@ -24,7 +24,7 @@ bool File::unref() const
 {
     if (deref_base())
         return false;
-    const_cast<File&>(*this).before_removing();
+    const_cast<File&>(*this).will_be_destroyed();
     delete this;
     return true;
 }

Kernel/FileSystem/File.h

@@ -75,7 +75,7 @@ class File
     , public Weakable<File> {
 public:
     virtual bool unref() const;
-    virtual void before_removing() { }
+    virtual void will_be_destroyed() { }
     virtual ~File();
 
     virtual ErrorOr<NonnullRefPtr<OpenFileDescription>> open(int options);

Kernel/Storage/ATA/AHCIPort.cpp

@@ -77,7 +77,6 @@ void AHCIPort::handle_interrupt()
             m_connected_device->prepare_for_unplug();
             StorageManagement::the().remove_device(*m_connected_device);
             g_io_work->queue([this]() {
-                m_connected_device->before_removing();
                 m_connected_device.clear();
             });
         } else {

Kernel/TTY/SlavePTY.cpp

@@ -29,7 +29,7 @@ bool SlavePTY::unref() const
         return true;
     });
     if (did_hit_zero) {
-        const_cast<SlavePTY&>(*this).before_removing();
+        const_cast<SlavePTY&>(*this).will_be_destroyed();
         delete this;
     }
     return did_hit_zero;