fix formatting in readme

Author: robryk

README.md

@@ -5,7 +5,7 @@ visual quality. Guetzli-generated images are typically 20-30% smaller than
 images of equivalent quality generated by libjpeg. Guetzli generates only
 sequential (nonprogressive) JPEGs due to faster decompression speeds they offer.
 
-# Building {#building}
+# Building
 
 1.  Get a copy of the source code, either by cloning this repository, or by
     downloading an