Tidy up metadata, headings, forms, and small accessibility fixes

src/data/site.ts

@@ -8,6 +8,6 @@ export default {
   image: {
     externalURL: `${import.meta.env.SITE}/nathan-cummins-composer-orchestrator-conductor.jpg`,
     src: "nathan-cummins-composer-orchestrator-conductor.jpg",
-    alt: "Nathan Cummins"
+    alt: "Picture of Nathan Cummins, Adelaide composer, orchestrator, and conductor"
   } as SiteImage
 };