fixup! diigo-cache: RSS in diigo's export shape, from cached items

A diigo note item's body (note_content) renders first, as a Highlight:
line, as the export does: the 6 "export has notes, cache none" items
from the comparison were notes whose bodies the cache had all along.

Generated-by: Claude Opus 5.5

diigo-cache/tests/rss.test.ts

@@ -21,6 +21,12 @@ describe("itemDescription", () => {
 		);
 	});
 
+	it("renders a note item's body as a Highlight line, as diigo's export does", () => {
+		expect(itemDescription({ type_name: "note", tags: "", description: "", note_content: "the note", annotations: [] })).toBe(
+			"Tags:no_tag;Description:;Annotations and Sticky notes:Highlight:the note\n",
+		);
+	});
+
 	it("says no_tag when there are no tags, and leaves empty parts empty", () => {
 		expect(itemDescription({ tags: "", description: "", annotations: [] })).toBe(
 			"Tags:no_tag;Description:;Annotations and Sticky notes:",