🚸 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/remarkDefaultTextRules.ts

@@ -0,0 +1,12 @@
+import { MARK_BOLD, MARK_CODE, MARK_ITALIC } from '@udecode/plate-basic-marks'
+import { getPluginType, Value } from '@udecode/plate-common'
+
+import { RemarkTextRules } from './types'
+
+export const remarkDefaultTextRules: RemarkTextRules<Value> = {
+  text: {},
+  emphasis: { mark: ({ editor }) => getPluginType(editor, MARK_ITALIC) },
+  strong: { mark: ({ editor }) => getPluginType(editor, MARK_BOLD) },
+  inlineCode: { mark: ({ editor }) => getPluginType(editor, MARK_CODE) },
+  html: { transform: (text: string) => text.replaceAll('<br>', '\n') },
+}