docs: improve clear-ssh-cache description (missed in previous commit)

Clarifies this clears hosts cached by SSH shell integration, completing
mitchellh's feedback on both action descriptions.

src/cli/action.zig

@@ -46,7 +46,7 @@ pub const Action = enum {
     /// List hosts cached by SSH shell integration for terminfo installation
     @"list-ssh-cache",
 
-    /// Clear Ghostty SSH terminfo cache
+    /// Clear hosts cached by SSH shell integration for terminfo installation
     @"clear-ssh-cache",
 
     /// Edit the config file in the configured terminal editor.