accounting: Make checkers show what they are doing

Before this change, all types of checkers showed "checking" after the
file name despite the fact that not all of them were checking.

After this change, they can show

- checking
- deleting
- hashing
- importing
- listing
- merging
- moving
- renaming

See: https://forum.rclone.org/t/what-is-rclone-checking-during-a-purge/35931/

fs/operations/check.go

@@ -120,7 +120,7 @@ func (c *checkMarch) SrcOnly(src fs.DirEntry) (recurse bool) {
 // check to see if two objects are identical using the check function
 func (c *checkMarch) checkIdentical(ctx context.Context, dst, src fs.Object) (differ bool, noHash bool, err error) {
 	ci := fs.GetConfig(ctx)
-	tr := accounting.Stats(ctx).NewCheckingTransfer(src)
+	tr := accounting.Stats(ctx).NewCheckingTransfer(src, "checking")
 	defer func() {
 		tr.Done(ctx, err)
 	}()
@@ -450,7 +450,7 @@ func (c *checkMarch) checkSum(ctx context.Context, obj fs.Object, download bool,
 	}
 
 	var err error
-	tr := accounting.Stats(ctx).NewCheckingTransfer(obj)
+	tr := accounting.Stats(ctx).NewCheckingTransfer(obj, "hashing")
 	defer tr.Done(ctx, err)
 
 	if !sumFound {