chore: Add @internal to createCSSStyles

Author: sidharthv96

packages/mermaid/src/mermaidAPI.ts

@@ -167,7 +167,7 @@ export const cssImportantStyles = (
 
 /**
  * Create the user styles
- *
+ * @internal
  * @param  config - configuration that has style and theme settings to use
  * @param  classDefs - the classDefs in the diagram text. Might be null if none were defined. Usually is the result of a call to getClasses(...)
  * @returns  the string with all the user styles