feat: update image handling

- removes old image shortcode
- update to latest 11ty image transform plugin

config/plugins/markdown.js

@@ -3,6 +3,7 @@ import markdownItFootnote from "markdown-it-footnote";
 import markdownItPrism from "markdown-it-prism";
 import markdownItAbbr from "markdown-it-abbr";
 import markdownItAnchor from "markdown-it-anchor";
+import markdownItImplicitFigures from "markdown-it-image-figures";
 
 const markdown = markdownIt({
   html: true,
@@ -13,6 +14,9 @@ const markdown = markdownIt({
   .use(markdownItFootnote)
   .use(markdownItAbbr)
   .use(markdownItAnchor)
+  .use(markdownItImplicitFigures, {
+    figcaption: true,
+  })
   .use(markdownItPrism, {
     defaultLanguage: "plaintext",
   });