fix: missing alt attribute on images even if provided (#679) (#685)

close #679

Co-authored-by: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>

src/node/markdown/plugins/image.ts

@@ -10,6 +10,15 @@ export const imagePlugin = (md: MarkdownIt) => {
     if (url && !EXTERNAL_URL_RE.test(url) && !/^\.?\//.test(url)) {
       token.attrSet('src', './' + url)
     }
+
+    if (token.attrIndex('alt') && token.children != null) {
+      token.attrs![token.attrIndex('alt')][1] = self.renderInlineAsText(
+        token.children,
+        options,
+        env
+      )
+    }
+
     return self.renderToken(tokens, idx, options)
   }
 }