Fix anchor in doc (#1902)

Signed-off-by: canghai118 <[email protected]>

Author: canghai118

docs/running.md

@@ -238,6 +238,6 @@ the same data:
 
 Add a chunk cache via `-memcached.hostname` to allow writes to be de-duplicated.
 
-As recommended under [Chunk encoding](#chunk_encoding), use Bigchunk:
+As recommended under [Chunk encoding](#chunk-encoding), use Bigchunk:
 
         -ingester.chunk-encoding=3 # bigchunk