🚸 Rewrite the markdown deserializer to improve br… (#1198)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Refactor**
- Updated markdown handling and serialization libraries for improved
performance and accuracy in text formatting.
- **New Features**
- Enhanced rich text and markdown conversion capabilities, providing
users with more reliable and seamless text formatting options.
- **Documentation**
- Added detailed documentation for markdown to rich text conversion and
vice versa, ensuring easier understanding and implementation for
developers.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/lib/markdown/convertMarkdownToRichText.ts

@@ -0,0 +1,69 @@
+import {
+  createPlateEditor,
+  createPluginFactory,
+  getPluginOptions,
+  isUrl,
+  Value,
+} from '@udecode/plate-common'
+import markdown from 'remark-parse'
+import { unified } from 'unified'
+
+import { DeserializeMdPlugin } from './deserializer/types'
+import { remarkPlugin } from './remark-slate/remarkPlugin'
+import { RemarkPluginOptions } from './remark-slate/types'
+import { remarkDefaultElementRules } from './remark-slate/remarkDefaultElementRules'
+import { remarkDefaultTextRules } from './remark-slate/remarkDefaultTextRules'
+import { deserialize } from './deserializer/deserialize'
+
+export const convertMarkdownToRichText = <V extends Value>(data: string) => {
+  const plugins = [createDeserializeMdPlugin()]
+  const editor = createPlateEditor({ plugins }) as unknown as any
+  const { elementRules, textRules, indentList } = getPluginOptions<
+    DeserializeMdPlugin,
+    V
+  >(editor, KEY_DESERIALIZE_MD)
+
+  const tree: any = unified()
+    .use(markdown)
+    .use(remarkPlugin, {
+      editor,
+      elementRules,
+      textRules,
+      indentList,
+    } as unknown as RemarkPluginOptions<V>)
+    .processSync(data)
+
+  return tree.result
+}
+
+export const KEY_DESERIALIZE_MD = 'deserializeMd'
+
+const createDeserializeMdPlugin = createPluginFactory<DeserializeMdPlugin>({
+  key: KEY_DESERIALIZE_MD,
+  then: (editor) => ({
+    editor: {
+      insertData: {
+        format: 'text/plain',
+        query: ({ data, dataTransfer }) => {
+          const htmlData = dataTransfer.getData('text/html')
+          if (htmlData) return false
+
+          const { files } = dataTransfer
+          if (
+            !files?.length && // if content is simply a URL pass through to not break LinkPlugin
+            isUrl(data)
+          ) {
+            return false
+          }
+          return true
+        },
+        getFragment: ({ data }) => deserialize<Value>(editor, data),
+      },
+    },
+  }),
+  options: {
+    elementRules: remarkDefaultElementRules,
+    textRules: remarkDefaultTextRules,
+    indentList: false,
+  },
+})