Fix broken ACON::Question docs (athena-framework/athena#565)

Author: Blacksmoke16

src/question/choice.cr

@@ -5,6 +5,8 @@ require "./abstract_choice"
 #
 # ```
 # question = ACON::Question::Choice.new "What is your favorite color?", {"red", "blue", "green"}
+#
+# helper = self.helper ACON::Helper::Question
 # color = helper.ask input, output, question
 # ```
 #
@@ -26,6 +28,8 @@ require "./abstract_choice"
 #
 # ```
 # question = ACON::Question::Choice.new "What is your favorite color?", {"c1" => "red", "c2" => "blue", "c3" => "green"}, "c2"
+#
+# helper = self.helper ACON::Helper::Question
 # color = helper.ask input, output, question
 # ```
 #

src/question/confirmation.cr

@@ -2,6 +2,7 @@
 #
 # ```
 # question = ACON::Question::Confirmation.new "Continue with this action?", false
+# helper = self.helper ACON::Helper::Question
 #
 # if !helper.ask input, output, question
 #   return ACON::Command::Status::SUCCESS

src/question/multiple_choice.cr

@@ -5,6 +5,8 @@ require "./abstract_choice"
 #
 # ```
 # question = ACON::Question::MultipleChoice.new "What is your favorite color?", {"red", "blue", "green"}
+#
+# helper = self.helper ACON::Helper::Question
 # answer = helper.ask input, output, question
 # ```
 #

src/question/question.cr

@@ -8,6 +8,8 @@ require "./base"
 #
 # ```
 # question = ACON::Question(String?).new "What is your name?", nil
+#
+# helper = self.helper ACON::Helper::Question
 # name = helper.ask input, output, question
 # ```
 #
@@ -22,6 +24,8 @@ require "./base"
 # ```
 # question = ACON::Question(String?).new "What is your name?", nil
 # question.trimmable = false
+#
+# helper = self.helper ACON::Helper::Question
 # name_with_whitespace_and_newline = helper.ask input, output, question
 # ```
 #