Fix subheader

README.md

@@ -8,7 +8,7 @@ Implementation of the Line Breaking Algorithm described in [Unicode Standard Ann
 Given an input text, locates "line break opportunities", or positions appropriate for wrapping
 lines when displaying text.
 
-# Example
+## Example
 
 ```rust
 use unicode_linebreak::{linebreaks, BreakOpportunity::{Mandatory, Allowed}};