docs(README.md): fix typo

README.md

@@ -180,7 +180,7 @@ var defaultOptions = showdown.getDefaultOptions();
    ```
    ![foo](foo.jpg =100x80)     simple, assumes units are in px
    ![bar](bar.jpg =100x*)      sets the height to "auto"
-   ![baz](baz.jpg =80%x5em*)  Image with width of 80% and height of 5em
+   ![baz](baz.jpg =80%x5em)  Image with width of 80% and height of 5em
    ```
  
  * **headerLevelStart**: (integer) [default 1] Set the header starting level. For instance, setting this to 3 means that