docs(accordion-item): update component description for vscode (#7611)

**Related Issue:** #6312 

## Summary
- Adds context to VS Code for the `accordion-item` component
- Tests our maintenance limitation when additional labels are present

packages/calcite-components/src/components/accordion-item/readme.md

@@ -1,6 +1,6 @@
 # calcite-accordion-item
 
-individual `calcite-accordion` item
+A child component of `calcite-accordion`, where some behavior is inherited from its parent such as the `appearance` and `selectionMode`.
 
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