Fixes link url

Author: wb36499

docs/administration-guide/gaffer-stores/accumulo-store.md

@@ -146,7 +146,7 @@ Gaffer can take advantage of Accumulo's built-in fine-grained security to ensure
 
 If no "visibilityProperty" is specified then the column visibility is empty which means that anyone who has read access to the table can view it.
 
-See [the visibility walkthrough](../security/security-guide.html#using-visibilities-for-fine-grained-security) for an example of how properties can be aggregated over different visibilities at query time.
+See [the visibility walkthrough](../security/security-guide.md#using-visibilities-for-fine-grained-security) for an example of how properties can be aggregated over different visibilities at query time.
 
 ## Timestamp