Add highlighting

package.json

@@ -73,14 +73,15 @@
     "lemmy-js-client": "^0.19.0-rc.13",
     "lodash.isequal": "^4.5.0",
     "markdown-it": "^13.0.1",
+    "markdown-it-bidi": "^0.1.0",
     "markdown-it-container": "^3.0.0",
     "markdown-it-emoji": "^2.0.2",
     "markdown-it-footnote": "^3.0.3",
+    "markdown-it-highlightjs": "^4.0.1",
     "markdown-it-html5-embed": "^1.0.0",
     "markdown-it-ruby": "^0.1.1",
     "markdown-it-sub": "^1.0.0",
     "markdown-it-sup": "^1.0.0",
-    "markdown-it-bidi": "^0.1.0",
     "mini-css-extract-plugin": "^2.7.5",
     "register-service-worker": "^1.7.2",
     "run-node-webpack-plugin": "^1.3.0",

src/shared/components/app/app.tsx

@@ -54,6 +54,11 @@ export class App extends Component<AppProps, any> {
             >
               {I18NextService.i18n.t("jump_to_content", "Jump to content")}
             </button>
+            <link
+              rel="stylesheet"
+              href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/atom-one-dark.min.css"
+            ></link>
+            <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js"></script>
             {siteView && (
               <Theme defaultTheme={siteView.local_site.default_theme} />
             )}

src/shared/markdown.ts

@@ -14,6 +14,7 @@ import markdown_it_html5_embed from "markdown-it-html5-embed";
 import markdown_it_ruby from "markdown-it-ruby";
 import markdown_it_sub from "markdown-it-sub";
 import markdown_it_sup from "markdown-it-sup";
+import markdown_it_highlightjs from "markdown-it-highlightjs";
 import Renderer from "markdown-it/lib/renderer";
 import Token from "markdown-it/lib/token";
 import { instanceLinkRegex, relTags } from "./config";
@@ -170,6 +171,7 @@ export function setupMarkdown() {
     .use(markdown_it_footnote)
     .use(markdown_it_html5_embed, html5EmbedConfig)
     .use(markdown_it_container, "spoiler", spoilerConfig)
+    .use(markdown_it_highlightjs, { inline: true })
     .use(markdown_it_ruby)
     .use(localInstanceLinkParser)
     .use(markdown_it_bidi);