[docs] document $store behavior more explicitely

Closes #4677

site/content/docs/01-component-format.md

@@ -177,7 +177,7 @@ If a statement consists entirely of an assignment to an undeclared variable, Sve
 
 A *store* is an object that allows reactive access to a value via a simple *store contract*. The [`svelte/store` module](docs#svelte_store) contains minimal store implementations which fulfil this contract.
 
-Any time you have a reference to a store, you can access its value inside a component by prefixing it with the `$` character. This causes Svelte to declare the prefixed variable, and set up a store subscription that will be unsubscribed when appropriate.
+Any time you have a reference to a store, you can access its value inside a component by prefixing it with the `$` character. This causes Svelte to declare the prefixed variable, subscribe to the store at component initialization and unsubscribe when appropriate.
 
 Assignments to `$`-prefixed variables require that the variable be a writable store, and will result in a call to the store's `.set` method.