Update docs/stats.md

Co-authored-by: Peter Ralph <petrel.harp@gmail.com>

Author: apragsdale

docs/stats.md

@@ -712,7 +712,7 @@ polarised where appropriate.
 
 The `site` mode computes two-locus statistics summarized over alleles between
 all pairs of specified sites. The default behavior, leaving `sites`
-unspecified, this method will compute a matrix for all pairs of sites, with
+unspecified, will compute a matrix for all pairs of sites, with
 rows and columns representing each site in the tree sequence (i.e., an n×n
 matrix where n is the number of sites in the tree sequence). We can also
 restrict the output to a subset of sites, either by specifying a single vector