Fix: Align Cache API definitions with Storage spec (#1789)

* Fix: Align Cache API definitions with Storage spec

This commit clarifies how the Cache API interacts with the underlying
storage mechanism, resolving ambiguity that stemmed from previous
specification language.

Key changes:
- Removes the direct association between "storage key" and "name to
  cache map".
- Defines "relevant name to cache map" as being retrieved via the
  `obtain a local storage bottle map` algorithm from the Storage
  specification, ensuring alignment.
- Updates the definition of `CacheStorage` to represent the
  `name to cache map` associated with its `environment settings object`,
  rather than the `origin`.
- Clarifying the definition of "relevant name to cache map" and its relationship with `CacheStorage`.
- Removing the explicit ID and avoiding indirect `[=this=]` usage.
- Ensuring consistent syntax for `[=name to cache map=]` references.

This makes the relationship between the ServiceWorker Cache API and the
Storage specification explicit and consistent, addressing the core issue
raised in #1784 and the follow-up
work in #1788.

Author: yoshisatoyanagisawa

docs/index.bs

@@ -1952,9 +1952,7 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
 
     A <dfn id="dfn-name-to-cache-map">name to cache map</dfn> is an <a>ordered map</a> whose [=map/entry=] consists of a [=map/key=] (a string that represents the name of a [=request response list=]) and a [=map/value=] (a [=request response list=]).
 
-    Each [=/storage key=] has an associated [=name to cache map=].
-
-    The <dfn id="dfn-relevant-name-to-cache-map">relevant name to cache map</dfn> is the [=name to cache map=] associated with the [=/storage key=] [=obtain a storage key|obtained=] from [=this=]'s associated [=CacheStorage/global object=]'s [=environment settings object=].
+    The <dfn>relevant name to cache map</dfn> for a {{CacheStorage}} object is the [=name to cache map=] associated with the result of running [=obtain a local storage bottle map=] with the object's associated [=CacheStorage/global object=]'s [=environment settings object=] and "<code>caches</code>".
   </section>
 
   <section>
@@ -2262,7 +2260,7 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
 
     The user agent *must* create a {{CacheStorage}} object when a {{Window}} object or a {{WorkerGlobalScope}} object is created and associate it with that <dfn for="CacheStorage">global object</dfn>.
 
-    A {{CacheStorage}} object represents a <a>name to cache map</a> of its associated [=CacheStorage/global object=]'s <a>environment settings object</a>'s [=environment settings object/origin=]. Multiple separate objects implementing the {{CacheStorage}} interface across documents and workers can all be associated with the same <a>name to cache map</a> simultaneously.
+    A {{CacheStorage}} object represents the [=name to cache map=] associated with the result of running [=obtain a local storage bottle map=] with its associated [=CacheStorage/global object=]'s [=environment settings object=] and "<code>caches</code>". Multiple separate objects implementing the {{CacheStorage}} interface across documents and workers can all be associated with the same [=name to cache map=] simultaneously.
 
     <section algorithm="cache-storage-match">
       <h4 id="cache-storage-match">{{CacheStorage/match(request, options)}}</h4>