Comment.
Setting page slug and text domain in constructor. Mapping out tasks.
Removing fields from SettingsSection class.
Removed SettingsArg class file.
Added addSection() method to Settings class.
Added registerSections().
Fixed variable name.
Removed registerSection().
Comments.
Removed TODOs.
Comments.
Comments.
Comments.
Added return value for chaining.
Moved parameters around.
Reworded error message.
Added addField() to SettingsSection. Added text domain as a property. Reworded error message.