INT-782 show rightmost tooltip on date minichart

(cherry picked from commit cc83c0a)

Author: Matt Cotter

src/minicharts/d3fns/date.js

@@ -168,7 +168,8 @@ var minicharts_d3fns_date = function() {
         };
       });
 
-      var innerWidth = width - margin.left - margin.right;
+      // without `-1` the tooltip won't always trigger on the rightmost value
+      var innerWidth = width - margin.left - margin.right - 1;
       var innerHeight = height - margin.top - margin.bottom;
       var el = d3.select(this);