feat(event): add WillCreateFile, WillRemoveFile (#2273)

node. These are mostly going to be useful for implementing lsp file
operation actions.

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/events.lua

@@ -10,7 +10,9 @@ M.Event = {
   NodeRenamed = "NodeRenamed",
   TreeOpen = "TreeOpen",
   TreeClose = "TreeClose",
+  WillCreateFile = "WillCreateFile",
   FileCreated = "FileCreated",
+  WillRemoveFile = "WillRemoveFile",
   FileRemoved = "FileRemoved",
   FolderCreated = "FolderCreated",
   FolderRemoved = "FolderRemoved",
@@ -52,11 +54,21 @@ function M._dispatch_node_renamed(old_name, new_name)
   dispatch(M.Event.NodeRenamed, { old_name = old_name, new_name = new_name })
 end
 
+--@private
+function M._dispatch_will_remove_file(fname)
+  dispatch(M.Event.WillRemoveFile, { fname = fname })
+end
+
 --@private
 function M._dispatch_file_removed(fname)
   dispatch(M.Event.FileRemoved, { fname = fname })
 end
 
+--@private
+function M._dispatch_will_create_file(fname)
+  dispatch(M.Event.WillCreateFile, { fname = fname })
+end
+
 --@private
 function M._dispatch_file_created(fname)
   dispatch(M.Event.FileCreated, { fname = fname })