Shell: Added a helper function isHelpRequest() (#7380)

* Added a helper function `isHelpRequest()`

* also handles combined short flags like -lh or -hl

* Created handleHelpRequest() helper function

encapsulates both:
Checking for help flags
Printing the help message

* Limit to reasonable length (2-4 chars total) to avoid matching long options like -verbose

weed/shell/command_fs_meta_notify.go

@@ -36,6 +36,10 @@ func (c *commandFsMetaNotify) HasTag(CommandTag) bool {
 
 func (c *commandFsMetaNotify) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {
 
+	if handleHelpRequest(c, args, writer) {
+		return nil
+	}
+
 	path, err := commandEnv.parseUrl(findInputDirectory(args))
 	if err != nil {
 		return err