Add missing RBS signatures

.rubocop.yml

@@ -154,3 +154,7 @@ Style/YodaExpression:
 
 Performance/ChainArrayAllocation:
   Enabled: false
+
+Style/RbsInline/MissingTypeAnnotation:
+  Exclude:
+    - 'test/**/*'

.rubocop_todo.yml

@@ -6,12 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 726
-# Configuration parameters: EnforcedStyle, Visibility.
-# SupportedStyles: doc_style, doc_style_and_return_annotation, method_type_signature, method_type_signature_or_return_annotation
-Style/RbsInline/MissingTypeAnnotation:
-  Enabled: false
-
 # Offense count: 193
 Style/RbsInline/UntypedInstanceVariable:
   Enabled: false

lib/gruff.rb

@@ -17,6 +17,8 @@
 #
 module Gruff
   # @private
+  # @rbs path: String
+  # @rbs return: String
   def self.libpath(path)
     File.join(__dir__, 'gruff', path) # steep:ignore
   end

lib/gruff/accumulator_bar.rb

@@ -18,6 +18,7 @@
 class Gruff::AccumulatorBar < Gruff::StackedBar
 private
 
+  # @rbs return: void
   def setup_data
     raise(Gruff::IncorrectNumberOfDatasetsException) unless store.length == 1
 

lib/gruff/area.rb

@@ -24,13 +24,15 @@ class Gruff::Area < Gruff::Base
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @sorted_drawing = true
     @fill_opacity = 0.85
     @stroke_width = 2.0
   end
 
+  # @rbs return: void
   def draw_graph
     x_increment = (@graph_width / (column_count - 1)).to_f
 

lib/gruff/bar.rb

@@ -51,6 +51,7 @@ class Gruff::Bar < Gruff::Base
   # Default value is +0.9+.
   #
   # @rbs space_percent: Float | Integer
+  # @rbs return: void
   def spacing_factor=(space_percent)
     raise ArgumentError, 'spacing_factor must be between 0.00 and 1.00' if (space_percent < 0) || (space_percent > 1)
 
@@ -59,6 +60,7 @@ def spacing_factor=(space_percent)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @spacing_factor = 0.9
@@ -68,6 +70,7 @@ def initialize_attributes
     @hide_labels = false
   end
 
+  # @rbs return: void
   def setup_drawing
     # Labels will be centered over the left of the bar if
     # there are more labels than columns. This is basically the same
@@ -92,6 +95,7 @@ def hide_bottom_label_area?
     hide_labels? && @x_axis_label.nil? && @legend_at_bottom == false
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
     return if @hide_line_markers
@@ -106,6 +110,7 @@ def setup_graph_measurements
     end
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #