Document where `column` param gets utilized in `substitute_at`.

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -307,8 +307,8 @@ def index_algorithms
 
       # QUOTING ==================================================
 
-      # Returns a bind substitution value given a +column+ and list of current
-      # +binds+.
+      # Returns a bind substitution value given a bind +index+ and +column+
+      # NOTE: The column param is currently being used by the sqlserver-adapter
       def substitute_at(column, index)
         Arel::Nodes::BindParam.new '?'
       end