Add Markdown support to CodeMirror component (#7961)

#### What type of PR is this?

/kind feature
/area ui
/milestone 2.22.x

#### What this PR does / why we need it:

Add Markdown support to CodeMirror component

#### Does this PR introduce a user-facing change?

```release-note
None
```

Author: ruibaby

ui/package.json

@@ -48,6 +48,7 @@
     "@codemirror/lang-html": "^6.4.11",
     "@codemirror/lang-javascript": "^6.2.4",
     "@codemirror/lang-json": "^6.0.2",
+    "@codemirror/lang-markdown": "^6.5.0",
     "@codemirror/lang-yaml": "^6.1.2",
     "@codemirror/language": "^6.11.3",
     "@codemirror/state": "^6.5.2",

ui/pnpm-lock.yaml

@@ -25,6 +25,13 @@ export const presetLanguages = {
     const { json } = await import("@codemirror/lang-json");
     return json();
   },
+  markdown: async (): Promise<LanguageSupport> => {
+    const { markdown } = await import("@codemirror/lang-markdown");
+    return markdown({
+      addKeymap: true,
+      completeHTMLTags: true,
+    });
+  },
 } satisfies Record<string, () => Promise<LanguageSupport>>;
 
 export interface CodemirrorProps {