Handle empty strings in code blocks

Signed-off-by: irma12 <irma@roadie.io>

.changeset/shaggy-ties-carry.md

@@ -0,0 +1,5 @@
+---
+'@backstage/core-components': patch
+---
+
+Handle empty code blocks in markdown files so they don't fail rendering

packages/core-components/src/components/MarkdownContent/MarkdownContent.tsx

@@ -65,8 +65,8 @@ type Props = {
 };
 
 const renderers = {
-  code: ({ language, value }: { language: string; value: string }) => {
-    return <CodeSnippet language={language} text={value} />;
+  code: ({ language, value }: { language: string; value?: string }) => {
+    return <CodeSnippet language={language} text={value ?? ''} />;
   },
 };