Merge pull request #47953 from p8/actiontext/document-rich-text-methods

Document ActionText::RichText methods [ci-skip]

actiontext/app/models/action_text/rich_text.rb

@@ -7,6 +7,16 @@ module ActionText
   # It also holds all the references to the embedded files, which are stored using Active Storage.
   # This record is then associated with the Active Record model the application desires to have
   # rich text content using the +has_rich_text+ class method.
+  #
+  #   class Message < ActiveRecord::Base
+  #     has_rich_text :content
+  #   end
+  #
+  #   message = Message.create!(content: "<h1>Funny times!</h1>")
+  #   message.content #=> #<ActionText::RichText....
+  #   message.content.to_s # => "<h1>Funny times!</h1>"
+  #   message.content.to_plain_text # => "Funny times!"
+  #
   class RichText < Record
     self.table_name = "action_text_rich_texts"
 
@@ -20,10 +30,26 @@ class RichText < Record
       self.embeds = body.attachables.grep(ActiveStorage::Blob).uniq if body.present?
     end
 
+    # Returns the +body+ attribute as plain text with all HTML tags removed.
+    #
+    #   message = Message.create!(content: "<h1>Funny times!</h1>")
+    #   message.content.to_plain_text # => "Funny times!"
     def to_plain_text
       body&.to_plain_text.to_s
     end
 
+    # Returns the +body+ attribute in a format that makes it editable in the Trix
+    # editor. Previews of attachments are rendered inline.
+    #
+    #   content = "<h1>Funny Times!</h1><figure data-trix-attachment='{\"sgid\":\"..."\}'></figure>"
+    #   message = Message.create!(content: content)
+    #   message.content.to_trix_html # =>
+    #   # <div class="trix-content">
+    #   #   <h1>Funny times!</h1>
+    #   #   <figure data-trix-attachment='{\"sgid\":\"..."\}'>
+    #   #      <img src="http://example.org/rails/active_storage/.../funny.jpg">
+    #   #   </figure>
+    #   # </div>
     def to_trix_html
       body&.to_trix_html
     end