Add gh shortcode for linking to github PRs or commit hashes

eleventy.config.ts

@@ -385,6 +385,19 @@ export default function (eleventyConfig: any) {
     }
   );
 
+  // Renders a link to a GitHub commit or pull request, in parentheses
+  eleventyConfig.addShortcode("gh", (id: string) => {
+    if (/^#\d+$/.test(id)) {
+      const num = id.slice(1);
+      return `<a href="https://github.com/${GH_ORG}/${GH_REPO}/pull/${num}" aria-label="pull request ${num}">${id}</a>`
+    }
+    else if (/^[0-9a-f]{7,}$/.test(id)) {
+      const sha = id.slice(0, 7); // Truncate in case full SHA was passed
+      return `<a href="https://github.com/${GH_ORG}/${GH_REPO}/commit/${sha}" aria-label="commit ${sha}">${sha}</a>`
+    }
+    else throw new Error(`Invalid SHA or PR ID passed to gh tag: ${id}`);
+  });
+
   // Renders a section box (used for About this Technique and Guideline / SC)
   eleventyConfig.addPairedShortcode(
     "sectionbox",