Added documentation to the FormBuilder class, should help
clarify issue #10115. Also made the field_helpers an explicit list of
methods.
Remove unecessary variable call, `#sort!` always returns an array
Remove unused block parameters
Merge pull request #10131 from Agis-/metal_helper

Remove unecessary variable call since `sort!` always returns the sorted array
Merge pull request #10130 from Agis-/patch-2

Mark unused block parameters.
Merge pull request #10122 from wangjohn/adding_documentation_to_form_builder

Added documentation to the FormBuilder class

Closes #10115