message: Refer to specification in the reference intro text
diff: # Language Reference
  -This part of the documentation is a reference-level description of the Fathom data description language.
  -This is intended for Fathom users who want a comprehensive description of Fathom's features,
  -but isn't intended to be a precise formal description.
  +This part of the documentation is a reference-level description of the Fathom data description language,
  +intended for Fathom users who want a comprehensive description of Fathom's surface-level features.
  +A more precise description of the concrete syntax, elaboration,
  +and core language of Fathom can be found in the [language specification].
  +
  +[language specification]: ./specification.md
  ## Summary
  