🚸 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/remark-slate/remarkTransformText.ts

@@ -0,0 +1,36 @@
+import { TText, Value } from '@udecode/plate-common'
+
+import { remarkDefaultTextRules } from './remarkDefaultTextRules'
+import { MdastNode, RemarkPluginOptions } from './types'
+
+export const remarkTransformText = <V extends Value>(
+  node: MdastNode,
+  options: RemarkPluginOptions<V>,
+  inheritedMarkProps: { [key: string]: boolean } = {}
+): TText | TText[] => {
+  const { editor, textRules } = options
+
+  const { type, value, children } = node
+  const textRule = (textRules as any)[type!] || remarkDefaultTextRules.text
+
+  const { mark, transform = (text: string) => text } = textRule
+
+  const markProps = mark
+    ? {
+        ...inheritedMarkProps,
+        [mark({ editor })]: true,
+      }
+    : inheritedMarkProps
+
+  const childTextNodes =
+    children?.flatMap((child) =>
+      remarkTransformText(child, options, markProps)
+    ) || []
+
+  const currentTextNodes =
+    value || childTextNodes.length === 0
+      ? [{ text: transform(value || ''), ...markProps } as TText]
+      : []
+
+  return [...currentTextNodes, ...childTextNodes]
+}