Require keyword params when initializing CellData and Position structs

lib/tabulo/cell_data.rb

@@ -5,6 +5,6 @@ module Tabulo
   # @attr source [Object] The member of this {Cell}'s {Table}'s underlying enumerable from which
   #   this {Cell}'s {Row} was derived.
   # @attr position [Position] The position of the {Cell} within the {Table}.
-  CellData = Struct.new(:source, :position)
+  CellData = Struct.new(:source, :position, keyword_init: true)
 
 end

lib/tabulo/column.rb

@@ -55,8 +55,8 @@ def header_cell
 
     def body_cell(source, row_index:)
       if body_cell_data_required?
-        position = Position.new(row_index, @index)
-        cell_data = CellData.new(source, position)
+        position = Position.new(row: row_index, column: @index)
+        cell_data = CellData.new(source: source, position: position)
       end
       Cell.new(
         alignment: @align_body,

lib/tabulo/position.rb

@@ -6,6 +6,6 @@ module Tabulo
   #   {Table} has index 0, the next has index 1, etc..
   # @attr column [Integer] The positional index of the {Cell}'s {Column}. The leftmost {Column}
   #   of the {Table} has index 0, the next has index 1, etc..
-  Position = Struct.new(:row, :column)
+  Position = Struct.new(:row, :column, keyword_init: true)
 
 end

spec/cell_spec.rb

@@ -14,12 +14,12 @@
   end
 
   let(:formatter) { -> (source) { source.to_s } }
-  let(:position) { Tabulo::Position.new(5, 3) }
+  let(:position) { Tabulo::Position.new(row: 5, column: 3) }
   let(:source) { "hi" }
   let(:styler) { -> (source, str) { str } }
   let(:value) { 30 }
   let(:width) { 6 }
-  let(:cell_data) { Tabulo::CellData.new(source, position) }
+  let(:cell_data) { Tabulo::CellData.new(source: source, position: position) }
 
   describe "#height" do
     subject { cell.height }