Add links to related specifications in intro.

Author: BigBlueHat

2024/json-ld-wg/index.html

@@ -153,8 +153,11 @@ <h2>Motivation and Background</h2>
           Use of JSON-LD has grown and expanded over the last decade (since it's first publication as a
           <a href="https://www.w3.org/TR/json-ld-api1/">W3C Recommendation in 2014</a>).
           JSON-LD remains a popular choice for encoding <abbr title="Seach Engine Optimization">SEO</abbr>-focused
-          structured data in Web pages. JSON-LD has also become a foundational format for social media (ActivityStreams),
-          Internet of Things data (Web of Things Description), Verifiable Credentials, and Software Bill of Materials (SPDX).
+          structured data in Web pages. JSON-LD has also become a foundational format for social media
+          (<a href="https://www.w3.org/TR/activitystreams-core/">ActivityStreams</a>),
+          Internet of Things data (<a href="https://www.w3.org/TR/wot-thing-description11/">Web of Things Description</a>),
+          <a href="https://www.w3.org/TR/vc-data-model-2.0/">Verifiable Credentials</a>, and Software Bill of Materials
+          (<a href="https://spdx.github.io/spdx-spec/v3.0.1/serializations/#serialization-in-json-ld">SPDX</a>).
         </p>
         <p>This growth in the applied use of JSON-LD has resulted in community interest in additional expressions of
           JSON-LD's underlying Linked Data structure in other formats. YAML-LD has been created by the