Adding documentation for markdown strings

packages/mermaid/src/docs/syntax/mindmap.md

@@ -162,6 +162,25 @@ Root
       C
 ```
 
+## Markdown Strings
+
+The "Markdown Strings" feature enhances mind maps by offering a more versatile string type, which supports text formatting options such as bold and italics, and automatically wraps text within labels.
+
+```mermaid-example
+mindmap
+    id1["`**Root** with
+a second line
+Unicode works too: 🤓`"]
+      id2["`The dog in **the** hog... a *very long text* that wraps to a new line`"]
+      id3[Regular labels still works]
+```
+
+Formatting:
+
+- For bold text, use double asterisks \*\* before and after the text.
+- For italics, use single asterisks \* before and after the text.
+- With traditional strings, you needed to add <br> tags for text to wrap in nodes. However, markdown strings automatically wrap text when it becomes too long and allows you to start a new line by simply using a newline character instead of a <br> tag.
+
 ## Integrating with your library/website.
 
 Mindmap uses the experimental lazy loading & async rendering features which could change in the future. From version 9.4.0 this diagram is included in mermaid but use lazy loading in order to keep the size of mermaid down. This is important in order to be able to add additional diagrams going forward.