LSPS5: clarify per-method cooldown to minutes (#64)

Adjusts rate limiting guidance to be on the order of minutes.
Rationale is that devices can miss one wake and be available shortly after,
so several notifications per hour should be acceptable.

Author: martinsaposnic

blip-0055.md

@@ -73,7 +73,7 @@ push notifications to be sent to actual mobile devices.
 Depending on architecture, the 'notification delivery service'
 and the 'mobile OS server' may not exist.
 For instance, a client running on a desktop environment might
-be able to periodically wake up and pool a 'notification
+be able to periodically wake up and poll a 'notification
 delivery service' without help from any kind of 'mobile OS
 server'.
 A client running on an environment where some DNS-resolvable
@@ -274,12 +274,12 @@ via the `lsps5.remove_webhook` call, which takes the parameters:
 
 ```JSON
 {
-  "app_name": "Another Wallet With The Same Signig Device"
+  "app_name": "Another Wallet With The Same Signing Device"
 }
 ```
 
 The following error is defined for `remove_webhook` (error
-`code` in parantheses):
+`code` in parentheses):
 
 * `app_name_not_found` (1010) - The specified `app_name` was
   not found.
@@ -626,16 +626,22 @@ For example, if a payment arrives and the LSP thus
 wants to send `lsps5.payment_incoming` notification to a
 registered webhook, and another payment arrives before the
 client comes online, the LSP must not send another
-`lsps5.payment_incoming` notification.
+`lsps5.payment_incoming` notification within its cooldown window.
 
 If the client does not come online after some time that a
 particular `method` was sent via a webhook, then the LSP
 may raise it again.
-This timeout must be measurable in hours or days.
+This timeout should be on the order of minutes.
 
 The timeout should be reset once the client comes online
 and then goes offline.
 
+> **Rationale** Mobile devices and networks are transient.
+> A device might ignore a wakeup due to battery or connectivity,
+> then accept one a short time later.
+> A cooldown on the order of minutes protects
+> against floods while improving delivery in practice.
+
 [LSPS0.ln_signature]: ./blip-0050.md#link-lsps0ln_signature
 [LSPS0.datetime]: ./blip-0050.md#link-lsps0datetime
 [RFC 1738]: https://datatracker.ietf.org/doc/html/rfc1738