Rename "Prompt Library" to "Rules Library" (#29349)

There's probably more to do to fully make the transition, and we'll
still debate a bit internally whether this is the name, but just opening
this PR up now for visibility.

Release Notes:

- N/A

crates/zed_actions/src/lib.rs

@@ -199,14 +199,14 @@ pub mod assistant {
 
     #[derive(PartialEq, Clone, Default, Debug, Deserialize, JsonSchema)]
     #[serde(deny_unknown_fields)]
-    pub struct OpenPromptLibrary {
+    pub struct OpenRulesLibrary {
         #[serde(skip)]
         pub prompt_to_select: Option<Uuid>,
     }
 
     impl_action_with_deprecated_aliases!(
         assistant,
-        OpenPromptLibrary,
+        OpenRulesLibrary,
         ["assistant::DeployPromptLibrary"]
     );