remove unused notification types on Linux and Mac

The PreModify and FileDeleted event notification types are
only used on Windows, or not at all, so we can remove them from
the Mac and Linux implementations.

This is akin to the changes made in fc85024193ba0a06dad12f620d6518b97f008779
to remove the NotificationMapping class on Mac and Linux.

Note that we do still send PreDelete event notifications, and per the
comments in GVFS/GVFS.Virtualization/FileSystemCallbacks.cs, the
FileSystemVirtualizers currently expect to only receive either PreDelete
or FileDeleted events, but not both, so removing the FileDeleted type
should align with this expectation.

ProjFS.Linux/PrjFSLib.Linux.Managed/CallbackDelegates.cs

@@ -35,9 +35,6 @@ namespace PrjFSLib.Linux
     public delegate Result NotifyFilePreConvertToFullEvent(
         string relativePath);
 
-    public delegate Result NotifyPreModifyEvent(
-        string relativePath);
-
     // Informational post-event notifications
     public delegate void NotifyNewFileCreatedEvent(
         string relativePath,
@@ -52,8 +49,4 @@ namespace PrjFSLib.Linux
 
     public delegate void NotifyFileModified(
         string relativePath);
-
-    public delegate void NotifyFileDeleted(
-        string relativePath,
-        bool isDirectory);
 }

ProjFS.Linux/PrjFSLib.Linux.Managed/NotificationType.cs

@@ -14,8 +14,6 @@ namespace PrjFSLib.Linux
         HardLinkCreated     = 0x00000100,
         PreConvertToFull    = 0x00001000,
 
-        PreModify           = 0x10000001,
         FileModified        = 0x10000002,
-        FileDeleted         = 0x10000004,
     }
 }

ProjFS.Mac/PrjFSLib.Mac.Managed/CallbackDelegates.cs

@@ -51,9 +51,6 @@ namespace PrjFSLib.Mac
     public delegate Result NotifyFilePreConvertToFullEvent(
         string relativePath);
 
-    public delegate Result NotifyPreModifyEvent(
-        string relativePath);
-
     // Informational post-event notifications
     public delegate void NotifyNewFileCreatedEvent(
         string relativePath,
@@ -69,8 +66,4 @@ namespace PrjFSLib.Mac
 
     public delegate void NotifyFileModified(
         string relativePath);
-
-    public delegate void NotifyFileDeleted(
-        string relativePath,
-        bool isDirectory);
 }

ProjFS.Mac/PrjFSLib.Mac.Managed/NotificationType.cs

@@ -15,8 +15,6 @@ namespace PrjFSLib.Mac
         HardLinkCreated     = 0x00000100,
         PreConvertToFull    = 0x00001000,
 
-        PreModify           = 0x10000001,
         FileModified        = 0x10000002,
-        FileDeleted         = 0x10000004,
     }
 }