Updated persistent_storage (markdown)

persistent_storage.md

@@ -16,10 +16,10 @@ If using the CLI, this data file location used is:
 - Microsoft Windows: `%APPDATA%/Apprise/cache`
 - Linux: `~/.local/share/apprise/cache`
 
-All Apprise URLs you define have a URL ID generated against them (`uid`).  To see what URL ID's have been assigned to your URLs, simply just use the `--dry-run` and pair it with `--all` to see everything:
+All Apprise URLs you define have a URL ID generated against them (`uid`).  To see what URL ID's have been assigned to your URLs, simply just use the `--dry-run` and pair it with `--tag=all` to see everything:
 ```bash
 # Given the command:
-apprise --dry-run --all
+apprise --dry-run --tag=all
 ```
 The output may look like this:<br/>
 ![Screenshot from 2024-08-22 21-06-24](https://github.com/user-attachments/assets/4df2f5c5-2b89-41d7-95c9-33c059e514a1)
@@ -167,10 +167,14 @@ class MyNotification(NotifyBase):
        with self.store.open("key", "rb") as fp:
            content = fp.read()
 
-       # To remove all persistent files you could use:
+       # To remove all persistent key/value pairs in cache you can do the following
        self.store.clear()
 
+       # The above is a clear all command: If you only wish to clear specific keys:
+       self.store.clear('key1', 'key2')
+
        # For consistency with the rest of the above logic:, this would clear a file
+       # by it's key with delete() instead of 'clear().
        self.store.delete('key')
 
        # multiple keys can be cleared if required