doc: wrong func name [skip ci]

Author: null8626

README.md

@@ -146,7 +146,7 @@ fn main() {
           return alert("There's no text!!!");
         }
         
-        textarea.value = decancer2(textarea.value);
+        textarea.value = decancer(textarea.value);
       }
     </script>
   </body>

core/src/lib.rs

@@ -146,7 +146,7 @@
 //!           return alert("There's no text!!!");
 //!         }
 //!         
-//!         textarea.value = decancer2(textarea.value);
+//!         textarea.value = decancer(textarea.value);
 //!       }
 //!     </script>
 //!   </body>